THE THURLOW CAST-STEEL GUN.
The Act of Congress of March 3, 1887, appropriated $20,400 for three rough-bored and turned cast-steel 6-inch guns, and under the proposals of the Navy Department two guns were received.
The first, the Pittsburg gun, of Bessemer steel, tempered, was proved at Annapolis, December 3, 1888. Its fate is well known, it having burst into numerous fragments at the first round, with service charge of 48¼ pounds of brown powder.
The Thurlow gun was cast of open-hearth steel, untempered, weight 13,100 pounds. The results of the physical tests made at Washington are as follows:
[TABLE]
The contour of the gun is a smooth curve, following in a general way the form of the built-up gun of the same caliber, but not showing its abrupt changes of exterior diameter. The trunnion band is screwed on. The exterior diameter over the powder chamber is 22.2 inches, and the diameter of the chamber at a corresponding point is 7.5 inches. Computing the pressure which the gun will endure at this point without being permanently deformed, using the highest clastic strength given by the tests, we find it to be, by Virgile’s formula, 13.8 tons per square inch. Using Clavarino’s formula, which gives a result probably much nearer the truth, we find the elastic strength of the gun at the same point to be 11.2 tons. The ordinary service pressure for 2000 f. s. initial velocity is 15 tons per square inch, and this pressure may be as much as doubled by an accident, such as the deformation of a weak shell in the bore, or by the powder becoming unduly quick owing to long exposure to a high temperature in a cruising vessel.
Computing the bursting pressure by Clavarino’s formula, using the highest tensile strength given, we find it to be 23.2 tons.
Before firing, the polished surface of the chamber showed a discoloration which had the appearance of a flaw, but the star gauge showed no difference of diameter, and there was no other appearance of any flaw.
The statutory test of ten consecutive rounds with service charges, fired as rapidly as possible, took place February 7, 1889. The gun had been carefully star-gauged, and the gauge laid away without breaking joints. Two rounds of 36 pounds were fired for the purpose of fitting the gas-check pad, and then ten rounds with a charge of 48¼ pounds Dupont’s O. P. C. brown pierced prismatic powder and a shell of 100 pounds. This charge in the 6-inch gun gives a pressure of 15 tons.
An examination of the bore revealed several flaws: near the scat of the shot, 5 feet 4 inches from the face of the breech, a flaw extending across the fifth band and groove to the right from the bottom of the bore; at 58 inches from the breech, a small flaw across the third and fourth bands to the left; at 58 inches, one extending across the tenth and eleventh bands to the left. The star gauge showed enlargements as follows:
[TABLE]
From a point 52 inches from the breech the enlargement gradually decreased at the rate of about .001 per inch, until at 90 inches it was practically nothing.
Such a result was to be expected from the calculated clastic strength of the gun. The contract required that it should not exhibit defects or weakness under the statutory test. None of the built-up guns have ever shown any enlargement under the statutory test, or under the abnormal pressures sometimes developed in experimental firing, and they have so large a factor of safety under present conditions that the Chief of bureau contemplates obtaining from them a higher muzzle velocity with increased working pressure.
C. S.
SPRENGEL’S EXPLOSIVES.
[Translated from Wagner's Jahres-Berichte der Chemie und Technologie, Vol. 20, 1874, by Karl Rohrer, Lieutenant, U. S. N.]
Note.—Enough time seems to have elapsed since these explosives were really discovered and given to the world for them to have disappeared, to a considerable extent, from the public memory, and in consequence of this fact they are being rediscovered in this country, England, Germany and other counties, and offered to the ordnance authorities of the day as something likely to revolutionize modern warfare. To refresh my own and the memory of the service I have made this translation.
Herman Sprengel has published a lecture upon a new class of explosive bodies which, during their fabrication, storage and transportation, are non-explosive, from which we extract the following:
With the object of discovering improved and other means for producing explosions than those already known and in use, the author observed the effect of a detonator upon numerous mixtures of explosive and combustible bodies. The components of the mixtures were proportioned in such a way that, theoretically, they should be perfectly oxidized and deoxidized. In the experiments, the author used steel and Brown’s patent detonator, which consists of a conical metal tube of about the strength of a goose-quill. Is 5.6 cm long and contains .65 grm. fulminate of mercury. Such a detonator was connected with the end of a safety-string fuse, commonly used in blasting; and the detonator, so connected and encased in a thin glass tube, was placed in the midst of the mixture whose explosiveness was to be determined. By igniting the free end of the string-fuse, the fulminate of mercury was presently caused to detonate, shattering its encasing tube and exerting its power upon the explosive charge of from 20 to 100 grm. contained in an open, wide-mouthed glass bottle.
As among the oxidizing agents which come into consideration, nitric acid, HNO3, contains the greatest quantity of oxygen disposable for combustion, i.e. 63.5 per cent (5/6 of its entire oxygen, which is 76.2 per cent), this body especially attracted the attention of the author. He found by experiment that under certain conditions, if any one of a number of organic substances was dissolved in nitric acid of about 1.5 sp. g., it became susceptible to explosion by detonation.
The hydrocarbon class furnishes the most suitable combustible substances which may be dissolved by nitric acid; as, however, when treated by the latter there ensues a violent chemical reaction, attended with great heat development, necessarily resulting from the formation of the nitro-compound, it is preferable, therefore, to dissolve this compound itself in nitric acid. If, for example, phenol (carbolic acid) is mixed with nitric acid, without the necessary precautions against accident, then the temperature of the mixture rises rapidly to the firing point. If, however, phenol, after treatment with nitric acid, that is, trinitrophenol (picric acid) is treated with nitric acid, the temperature falls, and to such an extent that this mixture may be used for refrigerating purposes.
It is extremely instructive to subject these mixtures and other well known explosive bodies, as gun-cotton and nitroglycerine, to a comparative analytical study. We submit the following in this connection:
(1). Nitrobenzol, C6H5(NO2) = 28.08
Nitric acid, 5(HNO3) = 71.92
100.00
Elementary composition before explosion. Probable composition after explosion.
C = 16.44 CO2 = 60.27
B.= 2.28 H2O = 22.55
N= 19.18 N = 19.18
O = 62.10
100.00 100.00
(2). Trinitrophenol (picric acid), C6H2(NO2)3O = 58.3
Nitric acid, 2 3/5 (HNO3) = 41.7
Elementary composition before explosion. Probable composition after explosion.
C = 18.33 CO2 = 67.20
H= 1.43. H2O = 12.83
N = 19.97 N = 19.97
O = 62.27
100.00 100.00
Gun-cotton, C6H7(NO2)3O6.
Elementary composition before explosion. Probable composition after explosion.
C= 24.24 CO2 = 55.52
H= 2.36 H2O = 21.24
N = 14.14 N = 14.14
O= 59.26 C = 9.10
100.00 100.00
Trinitroglycerine, C2H5(NO2)3O3.
Elementary composition before explosion. Probable composition after explosion.
C= 15.85 CO2 = 58.18
H = 2.20 H2O=: 19.80
N= 18.50 N = 18.50
O= 63.45 O = 3.52
100.00 100.00
These analyses prove that the new mixtures do not leave any inert residue—neither carbon, as gun-cotton, nor oxygen, as nitroglycerine, though in reality the decomposition does not take place so simply as is here indicated. It is evident that the elementary constitution of these mixtures may be variously modified, while the elementary constitution of chemical combinations is fixed and unalterable. By increasing or decreasing the quantity of the hydrocarbon it is possible to utilize all the oxygen for combustion and so produce carbonic oxide or carbonic acid, or a mixture of these two gases; in other words, to produce more gas and less heat, or less gas and more heat, as maybe done, for example, in the case of powder by changing the proportion of charcoal.
The mixture of nitrobenzol and nitric acid in the preceding proportions explodes with intense violence when fired by a detonator. Nitrobenzol dissolves readily in nitric acid, and if the solvent is weakened by water to 1.42 sp. g. is again precipitated. Upon mixing the two substances, at first there is development of heat; therefore when working with considerable quantities, some cooling arrangement will be required. In mixing 25 cubic centimeters the author observed increase of temperature to 50° C, By employing dinitrobenzol the temperature would probably fall. This mixture has the appearance of nitric acid, though the addition of 28 per cent of nitrobenzol to the acid appears to make it less volatile and less hygroscopic. Absorbed by infusorial earth and thoroughly incorporated with it, the mixture burns with a pale flame like dynamite, but not so lively. No inclination to explode was noticed while burning. The author found it very difficult to explode by concussion or shock, to do which he enclosed pellets of it in tinfoil and struck them upon an anvil. Guncotton and Nobel's dynamite, similarly treated, exploded upon receiving a materially weaker blow. The explosion of 35 grm. of the fluid mixture, contained in an open bottle, placed upon a wrought-iron plate of 6.5 mm. thickness, without tamping, made a deep indentation therein, the edges jagged. The explosion of a 35-grm. disk of gun-cotton upon another part of the plate produced an indentation with smooth edges and of less depth. Equal quantities (35 grm.) of the nitrobenzol mixture, gun-cotton and nitroglycerine, exploded upon fir plank of 7.6 cm. thickness, produced about equal results. The wood was cut through and splintered. It is to be regretted that as yet no exact method exists of comparing or measuring the force of detonating explosive bodies.
The following considerations led the author to believe that these new acid explosives would excel all heretofore known explosive bodies in development of force. As in the nitrobenzol preparation we are constrained to regard 5 atoms of the contained oxygen as not disposable for combustion, or already combined with the hydrogen of the nitric acid in the form of water, and as 3 molecules of the oxygen contained in the nitroglycerine, derived from the glycerine, (a triatomic alcohol) may be regarded in the same way, it follows that in the nitrobenzol mixture there remains 52.97 per cent, and in the nitroglycerine 42.3 per cent of oxygen for combustion, of which, however, owing to scarcity of combustible in the latter, only 38.77 per cent can be utilized. As the potential energy (or capacity for work) of a developed heat from a combustion process, and the quantity of oxygen consumed therein are mutually related, one may perhaps be permitted to regard the foregoing figures as a rough measure of the force of the two explosives in question. Therefore the author assumes that the force of nitroglycerine bears the relation to that of the nitrobenzol mixture as 38.77: 52.97 or 100: 136.6, If 1 molecule or 2 parts by weight of dinitrobenzol, and 4 molecules or 3 parts by weight of nitric acid, are taken, then the quantity of oxygen disposable for combustion in the mixture rises to 53.3 per cent.
How this and the other preparations will comport themselves when they are stored after their ingredients are mixed, the author is not able to state, as he made his experiments with them soon after mixing. Their ability to be exploded appears to be destroyed by the addition of a small quantity of water. At least he could not explode the nitrobenzol mixture under the above stated conditions when the nitric acid used in its preparation contained less than 25 per cent of the monohydrate. Confining the charge in a small space and employing a more powerful detonator might, perhaps, produce explosion when a more dilute acid was used. The high specific and latent heat of water, which would absorb the heat freed at the commencement of the explosion of the detonator, may account for this lack of explosiveness. The author cannot forbear to connect the remarkable explosiveness of fulminate of mercury with the fact that the specific heat of mercury is only one-thirtieth part of that of water. Fulminate of mercury contains 70 per cent of mercury. R. Bunsen observed, while gradually diluting explosive gas mixtures with non-combustible gases, that the explosiveness or inflammability of these mixtures suddenly ceased at a well defined limit or boundary.
Picric acid, to 58.3 parts, is readily soluble in an equivalent quantity of nitric acid, 41.7 parts. During the process of solution the temperature sinks below the freezing point. As the preceding mixture, so this explodes with great violence when fired by a detonator. Exclusive of the sixth part of the oxygen of the nitric acid, and that due to the phenol, there still remains 50.92 per cent disposable for combustion. It may be appropriate to say here that picric acid itself contains an oxygen mixture which is sufficient to make it a powerful explosive without addition of other oxidizing agent, and that it develops tremendous power when exploded by a detonator. Upon its explosion no smoke is formed. To show the intense heat which is developed upon the combustion of these mixtures, the author states this fact: a machine-made metallic cartridge case of 4.8 cm. length, 1.3 cm. diameter, and 11.4 grm. weight was charged with .65 grm. sporting powder and 1.3 grm. sand, which was moistened with scant .65 grm. of the solution of picric in nitric acid, the moistened sand coming after the powder, and a ball coming last. The cartridge so charged was at once placed in the cold bore of a Martini-Henry breech-loader and fired. Upon withdrawing the cartridge case it was found that the upper half of it had lost its shape entirely, the metal having been melted, and the particles of sand remaining were vitrified.
Instead of the two mentioned, there is a large number of combustible substances which may be used. It is not absolutely necessary that there shall be entire solution. The author succeeded in producing an explosive preparation by adding 17.4 parts of naphthaline to 82.6 parts of nitric acid of 1.5 sp. g. The mixture was of about half fluid consistency.
The author believes that his acid explosives must excel all other explosive bodies of this class thus far known, in the development of force. He rests his claim upon the consideration of the quantity of oxygen disposable for combustion which they contain. The nitrobenzol mixture contains, exclusive of the 5 atoms going to the hydrogen of the nitric acid, 52.97 per cent of oxygen; the picric acid mixture contains, if ½ of the oxygen of the nitric acid and that due to the phenol in the picric acid are excluded, 50.92 per cent of oxygen; nitroglycerine, however, if the 3 atoms of oxygen of the glycerine are excluded, contains only 42.3 per cent of oxygen, of which, owing to lack of sufficient combustible, only 38.77 per cent can be utilized.
The selection of an oxidizing agent is much more limited than that of a combustible body, that is, if complete transformation into gas is insisted upon. Among the former, nitrate of ammonia may be next considered, as it is composed of 35 parts nitrogen, 45 parts hydrogen, and 20 parts oxygen. Unfortunately, this salt is very hygroscopic, otherwise it could be used as an addition to or substitute for nitrate of potassium. The difficulty might be overcome by the use of air-tight cartridges and incorporating a non-volatile hydrocarbon as combustible for the 20 parts of oxygen. The author found that by addition of nitrate of ammonia to sporting powder there was a decided increase of initial velocity of the projectile, as follows:
[TABLE]
The ammonium powder was thoroughly mixed with the sporting powder before filling the cartridges; a little of the latter was reserved and scattered about the percussion cap.
Nitroglycerine may also be used as an oxidizing agent, as it contains a surplus of 3.52 per cent of oxygen, by adding a certain proportion of combustible. As free acid in nitroglycerine is the probable cause of terrible accidents, and is to be carefully avoided, therefore if, for example, aniline be added, which is readily soluble in nitroglycerine, a double advantage will be realized, as the aniline will neutralize the acid set free by gradual decomposition, and will also utilize the excess of oxygen contained, and so increase the explosive force of the body.
If we renounce the attempt to achieve complete gasification, we may turn to those explosive bodies whose oxidizing agents are salts of non-volatile bases. Of these, chlorate of potassium is especially observable. This salt yields explosive mixtures united with any one of almost all organic substances. As the mixing of it with combustible substances is a dangerous operation, the author employed fluid ones to avoid friction in mixing. These fluids were brought into contact with porous cakes or lumps of potassium, and absorbed by them quietly and without danger. Such lumps or cakes are obtained by pressing the moistened salt in suitable forms, which, upon drying, have about the consistency of loaf-sugar, and are more or less porous according as the salt is fine or coarse and whether the pressure is great or small. The author exploded detonators containing .65 grm. fulminate of mercury upon cakes so made and treated, without exploding them, and with this means he did not succeed in exploding them until the fluid combustible in the cake was impregnated with a certain proportion of sulphur or nitro-compound. Thus, for example, they exploded very violently upon adding a proportion of bisulphide of carbon; very violently upon adding a proportion of nitrobenzol; violently upon adding a proportion of ½ benzol + ½ bisulphide of carbon; violently upon adding a proportion of bisulphide of carbon saturated with naphthaline; very well upon adding a proportion of phenol dissolved in bisulphide of carbon; well upon adding a proportion of ¾ petroleum + ¼ bisulphide of carbon; not well upon adding a proportion of petroleum saturated with sulphur; not well upon adding a proportion of benzol saturated with sulphur.
If the decomposition of the bisulphide of carbon mixture proceeded in the order of the equation 2(KClO3 + CS2 = 2KCl + CO2 + 2SO2), then 100 parts chlorate of potassium would require 31 parts bisulphide of carbon. The author, however, secured better results by using a smaller quantity of the latter, 15 to 20 parts, as then, upon decomposition, sulphuric acid was formed. Upon using such a mixture in a granite quarry, it proved itself about four times as powerful as an equal quantity of blasting powder.
Although the simple, sulphur-free benzol mixture did not explode under the mentioned circumstances, it may be assumed, because of the similarity between concussion and detonation, that a body which is explosible by the former may also be exploded by the latter means, if strong enough initial effort is had. The author found, in fact, that when the detonator was surrounded with guncotton he could explode chlorate of potassium mixture, which contained neither sulphur nor nitro-compounds, as when mixed with benzol, petroleum, or phenol. Mixtures of this kind, in the form of 80-grm. cakes, placed upon a support in air, exploded with great development of power when the author acted upon them by the detonation of 15, 8, or 7 grm. of gun-cotton. The practical inference from these facts is apparent.
In these, as in the acid mixtures, many combinations and changes are possible and permissible. The chlorate of potassium can be partially, perhaps wholly replaced by nitrate of sodium. Instead of the indicated hydrocarbon, there may be used partially or entirely such as are non-volatile; even fats, bitumen, resin, and other rigid ones may be used, which have so low a melting point that it is practicable to saturate cakes of the oxidizing salt with them while in the melted state.
Objections to the use of several of the explosive bodies referred to can reasonably be made. The acid explosives are hygroscopic and very difficult to handle and manage because of the corrosiveness of the nitric acid. Further, it is not easy to find a suitable material for cartridge cases; the choice would be between glass, stoneware, and iron, and if the explosive is prepared for use in the form of dynamite, paper might answer. In respect to cheapness, effectiveness, safety, and reliability, these explosives compare favorably with all others now employed. The oxidizing agents in cake, lump, or granulated form, when impregnated with oily fluids, are protected against the injurious effects of water. The facts must not be lost sight of that about nine-tenths of all explosives produced, powder included, find their field of usefulness in blasting operations, and that the valuable and peculiar property which powder possesses as a propelling agent is not necessary in mining or blasting, as in this field we need, with few exceptions, the most powerful and at the same time the cheapest force. Upon these facts is based the author's hope of a future for the explosives under discussion.
Finally, and this may not be the least advantage possessed by these new explosive bodies, we may, to avoid danger during fabrication, storage, and transportation, keep the oxidizing agent separated from the combustible until such time as it is desired to have them act upon each other and to be made ready as an explosive body. This, of course, is easier of accomplishment when both agents are fluid, or at least one is so, than when both are rigid.
GUN-COTTON.
Its Military Applications, with Special Reference to the Latest Discoveries relating to Gun-Cotton Shells.
By Max Von Förster, Premier-Lieutenant a. D., Technical Director of the Gun-Cotton Factory of Wolff & Co., Walsrode.
[Translated, by permission of the author, by John P. Wisser, U. S. Army]
The gun-cotton factory of Wolff & Co., Walsrode, prepares compressed gun-cotton for military use. Although the quality, i.e. the chemical composition and the chemical properties, remains constant, the form of the gun-cotton varies with its application.
The principal applications are:
I.—For Stationary Submarine Mines.
For this purpose are largely used six-sided prisms, ¾ kg. in weight, with which any mine receptacle may be filled; or the receptacles for the charge, which are usually cylindrical in form, are filled with masses of gun-cotton of forms specially constructed for this purpose, which together exactly reproduce the interior form of the receptacle for the charge. In the first case the prisms are introduced separately in the mine; the opening for charging may therefore be small. In the second case the entire charge, collected in the receptacle therefore, is introduced at one and the same time into the mine; the opening for charging must therefore be large.
II.—For Movable Submarine Mines (Fish Torpedoes).
We fill the interior of the torpedo-head with gun-cotton, exactly corresponding to the interior space, bring the head up to a definite weight (which must be given us) and solder it up. In order to enable us to do this, all heads should, if possible, be sent to the factory in natura.
When this is not practicable, we prepare for the transportation and preservation of the gun-cotton special sheet-zinc vessels having the form of the torpedo- heads, and ship therein the charge.
The main mass of the gun-cotton used for mines and torpedoes is invariably wet, containing 15-25 per cent of water, as may be ordered; the priming charge consists of dry gun-cotton, from ½ to several kg. in weight, as may be required. The dry gun-cotton is always packed separately from the wet. The dry guncotton is detonated by means of a detonating primer filled with mercuric fulminate.
III.—For Shells, as Explosive Charge.
The principal kinds of such shells are:
1. Steel torpedo shells with thin walls and cast-iron shells.—We furnish new shells, or simply charges for such as are now on hand in the magazines and are to be adapted to gun-cotton. They are useful against objects of slight resistance; and in case of bomb-proof covers, such as casemates, powder magazines and hollow traverses, which are all covered with a considerable thickness of earth, they will pass through the latter, explode on the arches and act by their large bursting charge. The fuze is generally in the mouth. The shells are adapted to rifled mortars and howitzers.
2. Steel torpedo shells with thick walls and massive points.—The fuze is in the base (new fuze construction). These shells offer, besides the advantages of the shells under 1, the additional and most important advantages in that
a. On account of their strong walls and their construction, they may be fired not only from mortars, but from all guns, with however high an initial velocity, even above 600 m.
b. By their greater weight, their permanence and their massive points, they are capable of penetrating resisting objects such as granite masonry and cement arches; they therefore possess the immense advantage over the shells with a head-fuze under 1, that the bursting charge will explode and exert its effects not in front of the resisting objects, not on their exterior, but within the objects themselves. The bursting charge will therefore often have ten times the effect of the shells under 1.
The penetration of the shells in hard objects is rendered possible not only by their indicated properties, but also by our new base fuze applied to them, which, even when the shells are fired with the highest initial velocities and against the most resisting objects, does not break or explode prematurely, but acts with regularity, and allows the delay in the action of the fuze, for which it was set, to come into play.
3. Steel armor-plate shells.—Not so long as the shells under 2, with massive points, very thick walls, and therefore with but little space for the exploding charge.
Our explosive gun-cotton is, however, so strong that the necessarily small bursting charge is still capable of breaking the bottom and side walls of the shells into many small pieces, while the point remains in one piece, or is divided into but two or three parts, so that after the shell has pierced the plate, by means of the former excellent effect will be obtained against the men and the weak parts of the machinery in the interior of a battery, an armored ship, etc., and by means of the latter more energetic action against the strong parts of machinery.
As is well known, the charge of steel armor-plate shells has been entirely abandoned of late years, because it had been observed that it or the fuze, on account of the sudden shock, caused the armor-plate shell to burst before it had used up all its living force, and thus diminished its action. We have made possible again the use of a bursting charge in the armor-plate shell by means of our explosive and our new fuze, and therefore have again prepared a shell for these purposes. The shell had, so to speak, become a solid shot; it no longer burst, and the action of such a projectile, as is well known, is but slight.
Our explosive, in our special mode of application and our new fuze, will endure the greatest shock at the object struck without premature explosion, and will act with regularity and certainty.
Besides all the advantages thus far given, our explosive and this fuze insure the certainty that dangerous bore explosions, even with the highest initial velocities, are effectively excluded, which property allows the applicability of gun-cotton shells in casemates or onboard ship and in other confined spaces rendered especially dangerous by explosion taking place in them. We call especial attention to our fuze (base fuze). (See further on.)
Instructions for Charging Shells with Compressed Gun-Cotton.
A. Charging cast-iron or steel shells which are in a single piece and have the fuze in the head of the shell. (Wolff and Co's and Von Forster's system.)
1. Description of the gun-cotton and the mode of packing it, its transportation and preservation.—The gun-cotton is in the form of elongated grains, the cross-section of which is a rectangle of 10 to 18 mm. length of side, and their length is 25 to 50 mm. The grains are coated with a thin but compact layer of dissolved gun-cotton obtained by immersion in acetic ether. This layer prevents the crumbling and pulverization of the grains during transport and handling. The gun-cotton which is used for charging shells contains as a rule 20 per cent of water, but there is nothing to prevent the use of such as has but little water. The water renders the gun-cotton incombustible and not sensitive to even the most violent shocks, and the gun-cotton can be detonated only by a fuze specially arranged for the purpose.
Gun-cotton is, therefore, a substance which can be called an explosive only when in the hands of persons who have special charge of it and are in possession of the necessary means of ignition.
Wet gun-cotton, as regards its transportation, preservation and manipulation, is perfectly free from danger, and dry gun-cotton, properly handled, is also perfectly safe in these respects. Dry gun-cotton is not dangerous to store, and, in case it is set on fire by a fire from without, will not explode, if properly packed according to our method. Dry gun-cotton is therefore considerably less dangerous than gunpowder.
The gun-cotton is packed in wooden chests containing interior cases of sheet zinc. The latter are air-tight and prevent the evaporation of the water of the wet gun-cotton, or the absorption of moisture by the dry gun-cotton. Every such case has on the upper side an opening, closed with a cover, and serving for filling and emptying. In these chests the gun-cotton is transported and stored, and the chests remain closed as they come, until the gun-cotton is to be used.
As a magazine, any house of whatever construction is suitable, but the most suitable are such as are simple, light, above ground and not moist. Although all danger is excluded, it is preferable on general grounds to place these buildings, in case they contain large quantities of gun-cotton, not nearer, as a rule, to towns than 150 m. A wall about the magazine is superfluous, and in case of an explosion in the magazine is even harmful, since it would serve to confine and therefore strengthen the energy of the explosion.
2. Charging of the shells.—The shells are charged with the gun-cotton through the mouth and are filled out with liquid paraffine, which fills all the interstices between the grains themselves, as well as those between the latter and the shell walls, and after solidification makes a solid mass of the grains, whereby, in firing, a shock or the friction of the gun-cotton against the walls of the shell is rendered impossible.
The fuze extends outward beyond the opening and inward into the shell, since it must be in direct contact with the charge in order to be able to detonate it. In order to secure in the interior of the shell a place for the fuze, the charging is conducted as in the case of shrapnel. In introducing the last portion of the charge, and for the introduction of the paraffine, a charging funnel is used quite similar to the truncated cone used in loading shrapnel. The paraffine is mixed with half its weight of Carnauba wax*, and thereby acquires a high melting point, which may rise to 70° centigrade.
In case a smaller proportion of wax is taken, the melting point is lower. The paraffine is melted in the water-bath, or in a vessel over the fire direct. The paraffine does not become heated to a higher temperature than its proper fusing point till nearly all is melted. As soon as this takes place, however, the temperature rises rapidly. The paraffine, ready for introduction, should be heated to +80°-85° C, and rapidly introduced.
After 20 minutes to ½ hour, according to the size of the shell, the paraffine is cold and the charging funnel is unscrewed. In the interior of the shell a hollow space is left, exactly large enough to receive the fuze. This space is kept open during transportation and handling.
3. The Fuze.—The fuze consists of: (1) the fuze proper, as a rule a percussion fuze with safety arrangement and with a percussion cap; (2) the detonating primer; (3) the priming cartridge of dry gun-cotton.
When the shell strikes the object, the percussion fuze acts, the fire of the cap inflames the primer, this detonates the priming cartridge, and the latter the charge.
In case no cause of delay in action is affected in the fuze, the shell bursts immediately on striking, provided the blow be sufficiently strong to bring the percussion fuze into action.
But since a certain amount of penetration of the shell into the object is generally desirable and necessary for its proper action, all our fuzes, unless otherwise definitely ordered, have their action delayed by means of a column of compressed gunpowder.
The charging of the shells, the insertion of the fuze, the loading of the gun are entirely safe.
Explosions in the bore are not to be expected. We have fired several hundred shots from mortars, howitzers and guns, with the usual service charges, without a single dangerous explosion in the bore.
In the summer of 1887, in the course of further experiments in Pola in conjunction with the Austrian navy, we fired 50 shots from the 15 cm. gun, of cast-iron gun-cotton fuze shells with 516 m. initial velocity, with good results.
B. Charging shells which have a movable head or base, and are therefore in two parts.
These shells are loaded with gun-cotton in the form of disks, corresponding in diameter with that of the interior of the shell.
Since in charging with these disks less interspace is left between the pieces of gun-cotton than in charging with granulated gun-cotton, the weight of guncotton required is some 25 per cent higher.
With reference to the transportation and storage of gun-cotton, as well as the charging of the shells and the loading of the gun, everything, unless special constructions are required, is the same for disk-charging as for granule charging.
Shells with Base Fuze.
Shells with a fuze in the head are capable of penetrating objects not too compact, such as earthen breastworks, earthworks, walls, and woodwork, and, after using up its living force, of acting by its bursting charge.
In objects of great resistance, however, such as armor plates, concrete shields, or granite masonry without earth covering, they cannot penetrate, because they burst immediately on striking the hard object, provided they come with a comparatively great final velocity; the fuze in this case causes a premature explosion.
Although, even under these circumstances, the effect on hard arches, etc., under the earth covering, in consequence of the great detonating power of the gun-cotton, will be quite considerable, it will nevertheless be many times greater than this should the shell be able to penetrate into the hard object, or pass through it and act explosively inside of the covering, e.g. in case of a fort, in the interior enclosed with iron or free arches of harder material, or in case of an armored vessel, in the interior of the armored turret or the armored battery.
It is assumed that the shell can stand the shock against the object without breaking. A strong, thick-walled steel fuze shell, as, for instance, the ordinary Krupp steel fuze shell, 4 ½ calibers long, supplied with a base fuze arranged for the detonation of gun-cotton and a massive point, must be used, or, for firing against strong armor plates, a steel armor shell with a similar fuze.
For these two kinds of shells particularly the author has constructed a base fuze which may also be used for weaker shells, such as cast-iron or thin-walled steel shells, and which possesses the following advantages:
1. It permits of giving the steel torpedo shells and the other fuze shells a massive point, and thereby renders them much more capable of resisting the shock on striking the object.
2. It permits of again giving the steel armor shells a bursting charge (which at the present time has been generally abandoned in the case of these projectiles), as it is so constructed that, even in firing against the most resisting objects, such as armor plates, it does not cause the shell to explode directly on striking the object, as all other fuzes heretofore used do in such cases, but, on the contrary, gives the shell time to penetrate so far into the target as its solidity, its living force and the angle of impact may determine, and only after the time required for this purpose will it cause the charge to detonate and the shell to burst.
It is evident that, when the shell breaks on impact, as is the case when a shell strikes an armor plate obliquely, it cannot penetrate appreciably into the plate, and the explosion will in consequence accomplish little. But, in all firing in time of war, only a small proportion of the shells fired will probably strike the object aimed at, and especially an armor plate, and of these a still smaller number will so strike the plate as to pass through it.
It must therefore be acknowledged that if the shell does not pass through the armor plate the explosion cannot be very effective. Moreover, not only the shell but also its charge will have been wasted. It appears to us, however, that the fewer the shells which will penetrate through the armor plates into the battery within, the more necessary it is to give them the conditions for most effective action, and that, to obtain increased effect, a charge of gun-cotton and our base fuze, after it is proven not to act injuriously, must be adopted for armor shells.
In like manner does our base fuze offer great advantages for other long and short gun-cotton shells, in that it renders them more effective in their action against objects of great resistance. These will include, besides bomb-proof covers of the latest construction, the armored shields, covered with a beton or granite layer, of the armored land turrets. We may expect to remove the glacis and then the armored shield, and to fire against the turret itself, and indeed against its exposed under-parts.
3. This new base fuze mainly and effectively excludes all possibility of premature explosions in the bore of the gun which may endanger it. We may remark incidentally that this base fuze differs essentially from the head-fuze used by us, not only in its properties but also in its construction.
Firing Experiments carried on with the Author's Assistance.
I. Firing -with gun-cotton shells, carried on by the Royal Italian Land Artillery, on the firing grounds at St. Maurice and in Spezia, in the years 1886-7.—The object of the experiments was to provide the cast-iron shells of the siege and seacoast guns already on hand, as well as newly constructed steel torpedo shells, with a bursting charge of gun-cotton and a suitable fuze, and to fire the shells with the customary service initial velocities.
The experiments were very extensive and gave the following favorable results:
- The gun-cotton shells may be fired with safety, without fear of premature explosions in the bore.
- The shells explode at the proper moment at the object.
- Chemical and practical experiments show that the gun-cotton employed is pure and chemically stable, so that it can be stored by itself or enclosed in the shell without danger, and finally, that the mode of charging the shell is sufficiently simple, without danger and practicable.
The system used for charging the shells was that patented by Wolff & Co, and Von Forster. The gun-cotton, as already stated, is in the form of long grains; after charging the shell the latter is filled with paraffine, in such wise as to fix the gun-cotton grains in position and fill the interstices with paraffine; the charge thus forms a compact mass, preventing thereby jamming or rubbing on the walls of the shell.
As fuze was employed the percussion fuze heretofore used with the respective shells, after having been previously made applicable to the special object here arising.
Ordinary cast-iron shells with gun-cotton and fuze were fired from:
- The 15 cm. gun, initial velocity 400 m., reduced charge. Weight of shell, complete, 30 kg.; charge of shell 1.4 kg. gun-cotton, range 5000 m.
- The 15 cm. rifled mortar with an initial velocity of 208 m.; shell as in 1.
- The 21 cm. howitzer, initial velocity 250 m., weight of projectile 80 kg., charge of shell 3.7 kg., range 4000 m.
- 24 cm. howitzer, initial velocity 231 m., range 4000 m. 24 cm. mortar, initial velocity 240 m., weight of projectile for each of the two pieces 121 kg., charge of shell 7 kg.
- 28 cm. howitzer, initial velocity 307 m., range 6700 m.
The shell has a hardened massive point and a base fuze. Weight of projectile, 220.5 kg.; charge of shell, 7.7 kg. The steel torpedo shells were fired from the 21 cm. howitzer and the 15 cm. mortar. Charge of the 21 cm. shell, 20 kg.; range, 3500 m.
Effect of the shells in earth.—The fuzes of the shells were delayed in action, the shells were fired at high elevations and penetrated, with their high angle of fall, very deep into the earth, and therefore produced as a rule no funnel at the surface. At the firing grounds at St. Maurice the subterranean action was, however, measured by the disturbed and loosened earth, and gave as a comparison between gun-cotton and gunpowder shells the following results:
The sphere of action of gun-cotton shells in earth is somewhat greater than that of gunpowder shells. The extent of this space alone does not, however, furnish an accurate measure of the action of the two kinds of shells, but the energy developed within this space must also be considered before making any comparisons.
The gun-cotton shell triturates and pulverizes the earth in its sphere of action; the gunpowder shell simply loosens it. From this it must be concluded that a resisting object (as, for instance, a stone arch, an iron protection), which lies within the sphere of action of the explosion of gun-cotton shells, will be disturbed, while it will suffer very little from gunpowder shells.
In order, therefore, to measure the energy of the gun-cotton shell, a correspondingly definite problem must be set for it. As a matter of fact, the experiments previously made in Italy and elsewhere with this object in view also showed the great superiority of gun-cotton.
At all events, the gun-cotton shell, even though it be simply a question of the simple removal of an earth covering, which will seldom be required and will always be very tiresome, will still show its superiority, as is proven by the following numbers taken from these experiments at St. Maurice.
The extent of the spheres of action was determined from the mean of a number of shots in the following measures (the last indicating the depth):
15 cm. gun-cotton shell, 3.2 X 2.2 X 1.2 m.
15 cm. gunpowder shell, 1.8 X 1.7 X 1.9
21 cm. gun-cotton shell, 3.6 X 3-4 X 2.3
21 cm. gunpowder shell, 3.2 X 2.9 X 2.0
24 cm. gun-cotton shell, 4.7 X 4.7 X 2.0
28 cm. gun-cotton shell, 4.0 X 4.0 X 3.0
28 cm. gunpowder shell, 4.0 X 4.0 X 2.0
One of the 28 cm. shells made in addition a subterranean cavity 2 m. X 2 m. X 1-5 m.
A 24 cm. gun-cotton shell which did not penetrate as deeply into the earth as the others, made a surface funnel of 4.5 m. diameter, 1.5 m. depth.
The 21 cm. steel torpedo shells made surface funnels of 5.3 m. diameter, 1.5 m. depth, on the average.
A torpedo shell buried horizontally in earth at a depth of 1.25 m. with a charge of 20 kg., produced an explosion funnel of 5.5 m. diameter and 2.4 m. depth.
For the Italian 15 cm. and 21 cm. steel torpedo shell we also furnished guncotton in the form of disks, and the experiments with these too gave good results.
After the method of charging the shells in its details was decided upon and proved satisfactory, an experiment on a large scale and corresponding to reality was undertaken on the 2d of November, 18S6, at Spezia, carried out to determine the action of gun-cotton shells on an experimental pontoon provided with an armored deck. Cast-iron gun-cotton shells were fired against it from the 24 cm. howitzer, and with such effect that it soon sank to its middle under water, and was only held afloat by its water-tight compartments.
On the action of gun-cotton shells, those 5 calibers in length, for instance, against fortifications, Lieutenant-General Brialmont, "La fortification du temps present," 1885, Bruxelles, and also Snyders in the Militaire Spectator de Breda: "Schietkatoen en Schietkatoengranaten," and other authors, give results and figures, and all praise the high degree of efficiency of gun-cotton shells, adding that these shells will have the greatest effect on sieges and the construction of fortifications.
Note.—The preceding experiments have led in a large degree to the introduction of gun-cotton shells in Italy. The Uispensa XII of the year 1887 of the official Giornale d'Artiglieria e Genio contains three War Department orders, dated December 1, 1887, in which granulated gun-cotton (system of Wolff & Co. and V. Forster) is introduced for the 24 cm. mine shell, while for the 15 cm. and 21 cm. torpedo shells a charge of gun-cotton disks is selected.
II. Firing Experiments of the Royal Italian Navy in Viareggio and Castagna in April, 1887.—The experiments consisted in firing cast-iron shells charged with gun-cotton in the form of grains from the 228 mm. gun with 10 kg. and 17 kg. gunpowder, and from the 254 mm. gun with 18 kg. and 24 kg. gunpowder.
After it was proven by these experiments that the shells could be fired without exploding in the bore, and that they burst properly at the target, experiments were made against a target composed of compactly stamped coal, and the shells distinguished themselves by their great detonating action.
III. Results of the firing of steel armor shells with gun-cotton and fuzes (system of Wolff & Co. and Von Forster), carried out by the Austrian Navy in the summer of 1887, in Pola.—Gun: Uchatius' 15 cm. bronze gun; steel armor shell, weight complete, charged, 39.400 kg.; base fuze, gunpowder firing charge, 9.5 kg.; initial velocity, 476 m.; 300 grams gun-cotton as bursting charge.
Target 65 m. distant, consisting of armor plates of the best Stayer forged iron some 12 cm. thick, fastened between supports in the form of trestles of strong wood.
1. Firing against two such plates placed close together, one behind the other, bolted together; 6 m. in rear is a wooden target of 4 cm. thick fir boards, and behind this an earthen rampart. The shell passed through both plates, and burst behind them, the pieces piercing the wooden target and penetrating as much as ½ m. deep into the earthen rampart.
2. Firing against three such plates, placed close together, one behind another and bolted together, backings as above. The shell passed through two plates and penetrated into the third so far that its point just projected beyond it, and exploded in this position after it had expended its entire living force in penetrating the armor plate.
3. Explosion of such a 15 cm. steel armor shell, like that under Experiments 1 and 2, charged with gun-cotton, in amine.
The shell gave the following explosion pieces:
The point remained entire 9.220 kg.
1 piece 1.700 kg.
1 piece 1.320 kg.
1 piece 1.150 kg.
14 pieces between 1 kg. and 0.5 kg.
86 pieces, in toto 12.5 kg.
29 pieces 1.5 kg.
The result must be regarded as very favorable.
The point and the heavy explosion pieces preserved sufficient weight to act effectively against parts of machinery, gun-carriages in the interior of a ship or turret, etc., besides which there are innumerable pieces which will act very effectively against the men under all circumstances, and in an enclosed battery quite destructively.
Explosion and Firing Experiments
carried out in the powder works of Cramer & Buchholz, Rubeland, on the 19th of March, 1888, by Wolff & Co., Walstrode, in the presence of representatives of the Imperial German Admiralty, the Royal Prussian War Department, the Royal Italian Navy, and the Royal Italian War Department.
I.—Firing Experiments.
Gun.—21 cm, reinforced gun, 22 calibers long, Krupp breech-loader. Firing Charge of Gunpowder—Brown prismatic powder P. P. C/82 of Cramer & Buchholz, Rubeland.
Projectile.—Krupp steel shell with massive point, constructed as an armor shell, 2 ½ calibers long, weighing 98 kg. charged.
Bursting Charge.—1 kg. wet gun-cotton in the form of grains, covered with a coating by means of acetic ether. After the insertion of the charge, the shell is filled with paraffine so as to fill up all the interstices and fasten the charge in position. Room for the fuze is left.
Fuze.—The fuze is at the base, attached to the base screw, construction of Wolff & Co. and V. Forster. The fuze is a percussion fuze and takes up on impact a position different from its original position, in which second position only can it act on the bursting charge. (See pp. 5 and 6, and 13, 14 and 15 of the MS.) It contains an adjustable means of delaying its action.
Target.—A compound armor-plate of 12 cm. thickness, drawn from the Dilling furnace, and a wooden backing of 60 cm. oak wood in two beams. Below are 4 bolts, above 3 bolts, to fasten the plate; the bolts do not reach through the entire plate. Plate and backing are supported in front and rear by two trestles. The plate is 255 cm. broad and 170 cm. high. Behind the plate there is an explosion chamber lined with beams, the rear wall of which consists of a double layer of pine trunks 24 cm. thick and separated from the plate 5.60 m. The chamber is covered with earth externally, and the rampart in rear is 3.50 m. thick below and 1 m. at top.
Shot 1.—An uncharged steel armor shell, brought up to the weight of the charged shell, gunpowder firing charge 22 kg.; initial velocity, as near as could be determined, 420-430 m.
Result.—The shell passed smoothly through the plate, the wooden backing, the rear wall of the explosion chamber, and penetrated into the earthen rampart, where its path could be traced for 2 m., and continued into the subjacent soft ground.
Shot 2.—A complete steel shell, as previously described, charged with guncotton and provided with fuze; gunpowder firing charge 22 kg.
Result.—The shell passed smoothly through the plate, leaving an opening just like the uncharged shell, then through the wooden backing, the rear wall of the explosion chamber, penetrated the earthen rampart, was deflected upward in the latter and passed through it in its upper weaker part. On emerging from the rampart it exploded in the air, as was evidenced by the strong detonation, easily distinguishable from that of a charge of gunpowder.
Shot 3.—Charged steel shell, and gunpowder charge of gun as in No. 2.
Result.—The shell, like No. 2, passed through plate, backing and rear wall of explosion chamber, and exploded about 2 m. behind the latter in the rampart. In the latter there was a funnel of 2/3 m. depth and 2 ½ m. diameter. Several explosion pieces flew out of the rampart; they could be heard whizzing through the air.
Shot 4.—Charged steel shell as before; gunpowder firing charge 14 kg.
Result.—The shell passed through everything in like manner as No. 3, penetrated the rampart, burst there and threw out a funnel as large as No. 3.
Subsequently, in digging in the rampart, explosion pieces were found some 2 m. behind the rear wall of the explosion chamber, weighing in all 45 kg., of which the heaviest weighed 11.5 kg. and was a part of the base of a shell. Two other smaller pieces of the base were also found, and many explosion pieces of about 1 kg. weight. Of the point nothing has been found thus far, but in better weather the search will be continued.
II.—Explosion Experiments.
Three shells of the same construction and charged like the previously described steel shells, but made of cast iron, were placed in a mine, and the fuze, placed in its first position, in which it could not act so as to bring the charge to detonation, was detonated by means of a Bickford fuze.
Result.—The base screw was thrown out in shells Nos. 2 and 3; the charge, according to program, did not explode, however, in any of the shells; shell No. 1 received a crack from the opening in the base through the base and side wall, a copper band broke, but the shell was not burst asunder.
In shell No. 2 a piece about 1/3 the size of the base was torn out of the base and the shell was divided into two parts along its length.
Shell 3 was torn into three large and four small pieces.
The charge in case of shell 1 was found in the shell, in 2 and 3 it lay in little clumps and separate grains partly in the shell, partly in the mine.
The effect produced was brought about only by the priming cartridge of the fuze, which, if it be incapable of breaking asunder cast-iron shells or just barely capable of accomplishing this, will probably, in case of steel shells of great resistance, be only sufficiently effective to throw out the base screw.
Such explosion experiments are often carried on with the thinner-walled shells at the gun-cotton factory at Walsrode with a similar result: never does the explosion of the fuze in its first position bring the charge of the shell to detonation.
Although it is perfectly certain that the fuze will remain in this its first position till the shell strikes the object, yet in case of an explosion of the fuze in the bore of the gun (hence prematurely), no other effect than that just described could ever follow. That is, there may be a rupture of the shell, but never a detonation of the charge of the shell. Serious damage to the gun, bursting of the chase, must be regarded as specifically out of the question.
On the other hand, it has been proven by many experiments at the guncotton factory at Walsrode that the fuze will bring the charge to full detonation as soon as it is brought into the second position by the impact of the shell and exploded.
The results of the experiments here described may be summed up as follows:
(1) Gun-cotton armor shells were fired without accident from the 21 cm. gun with an initial velocity of 430 m.
(2) These shells passed through the 12 cm. thick compound plate, leaving an opening of the exact size of the shell, as well as the 60 cm. thick oak backing, then the rear wall of the explosion chamber, and finally 2 m. of earth; they therefore worked their way through an armor plate and several obstructions for a distance of some 8 m., and burst only after the delay effected in the fuze was over.
(3) The charge is sufficiently great to burst the strong thick-walled 21 cm. steel armor shells and break them up into pieces sufficiently large for effective action.
(4) The fuze offers every security against any premature explosions in the bore bursting the chase of the gun or otherwise seriously injuring it.
Since, then, the explosive used, wet gun-cotton in granular form, brings with it no danger either in its handling or as regards the shock which it receives in the shell in firing, and since, moreover, our method of charging, filling out the shell charged with granulated gun-cotton with melted paraffine, is in nowise dangerous, it appears to us that, by the important and guaranteed exclusion of premature bore explosions, the possibility of introducing gun-cotton as a charge for all shells is proven. The advantages presented by the stronger charge will in very many cases make this introduction desirable.
Is it desirable, however, as is the case very generally, to regard the shell charged with a sudden explosive only as a weapon for special purposes, and to limit one's self to long steel shells with the greatest possible charge for use in mortars and howitzers: even for this purpose does our new fuze recommend itself, the principle of which, let us remark, may be applied for ignition at the head of the shell as well.
AMORPHOUS CELLULOSE.
[Translated from the Mittheilungen aus dem Gebiete des Seewesens, Vol. XVI, No. X, 1888, by Albert Gleaves, Lieut., U. S. N.]
Amorphous cellulose is obtained from cocoanuts at the factory of Torrilhon & Co., Chamalieres, near Clermont-Ferrand. It is stated that the methods of its preparation are patented for all countries, but a similar preparation has been successfully made by a firm in Italy.
Torrilhon & Co. are chiefly manufacturers of rubber goods, such as rubber tubing, etc., for railroad brakes and other supplies of like nature, rain-coats for the officers and soldiers of the French Army, and various descriptions of weather clothing.
As already stated, the cellulose is made from cocoanuts. The method of manufacture is a secret, but it is known that it is not particularly difficult, and is accomplished by purely mechanical means.
Properties of the Cellulose.—Amorphous cellulose consists of the pith or meal and the fiber. The fiber has the natural color of the cocoanut and the strength of horse-hair. The fibers vary in length from three inches to twelve inches, and when twisted together resemble human hair.
The meal, the real cellulose and the main constituent of the "kofferdams," has also the peculiar brown color of the cocoanut, consists of small granules, and is mixed with numberless little threads of the fiber. The sp. gr. of the fiber and meal, in loose conditions and not compressed, is 65 kilos, per m3., and the sp. gr. of the compressed cellulose is 125 kilos, per m3. The cellulose absorbs a certain amount of water, and then by its inherent property of expanding when wet it fails to take up any more. C3wing to its small sp. gr., which is even less than that of cork, it makes an excellent material for life-preservers, and when used in great masses serves as a means to keep afloat a severely wounded battle-ship. Cellulose that has been thoroughly soaked can, after drying, be used with the same results as when fresh; its appearance only is changed, the color becoming lighter. When used as a floating belt for ships it is packed in the compartments .125 m. thick; it gives off no unpleasant odors, and is not liable to decay, and is said to undergo no change during two or three years' service. It is also reported that the passage of a projectile through it will not set it on fire, and in this respect it has a decided advantage over the caoutchouc belt, which, on being pierced by a shot, begins to glow and evolve a smoke so dense, unpleasant, and absolutely intolerable that it is almost impossible to get to the leak.
If dry cellulose in loose condition is ignited, it begins to smolder and give off a whitish transparent smoke not altogether unpleasant. It leaves a black residue which greatly resembles fine soot, and which is easily pulverized between the fingers.
The burning of the cellulose is retarded by the compression of packing; it is more difficult to inflame if it is compressed when moist, and impossible to do so when wet.
A fair idea of the action of cellulose is given by the following experiment: take an ordinary flask, fill it with water, and choke the neck with cellulose meal. Then invert the flask, and it will be found that the water will not run out at all, or only drop by drop.
Packing the Cellulose Belt of Ships.—When used as a leak-stopping material on board war-ships, the cellulose is mixed in the proportion of one part by weight of fiber and 15 parts by weight of meal. The operation of mixing is conducted as follows:
Upon a table 6 ½ feet square the fiber is thinly spread out in layers of .08 inch to. 1.2 inch. The fiber forms only a network upon which to pour the meal, which is spread upon it in a layer from 1.6 inches to 2 inches in thickness and evenly distributed by hand. The entire part is then divided into strips 6 inches or 8 inches wide (6 ½ feet long). It is then ready for packing in the compartments.
The bottom of the compartment is entirely covered with the separate pieces; upon this layer a second, third, and eventually a fourth layer are laid. Upon this last layer a light board cover is placed, and upon the cover heavy weights or lead plates. If it is possible for a man to get into the compartment, the simplest way to pack the cellulose is by the weight of his body. The weights should be left on for a few minutes, and then fresh layers introduced and pressed in the same manner until the compartment is full. The man-hole plates are then screwed up. It is neither necessary to ventilate the compartments nor to examine them at regular intervals.
Amorphous cellulose is stowed by the Government or private firms in bales of one to five tons. Both meal and fiber are packed in sacks which bear the mark of the factory. These sacks are 65 inches high and 94.5 inches circumference; they contain no pounds of meal and fiber not compressed, or 176 pounds compressed. As in both cases the cellulose is pressed together, it is advisable, before using it, to empty it out of the sacks and let it resume its natural thickness.
Price.—1 kilo, of meal at the factory costs 1.75 francs. The cost of packing and transportation to the railroad station near Chamalieresis 10 to 15 centimes per sack. The weight of the sack is included with the cellulose.
Cellulose in the French Navy.—The French service was the first to adopt cellulose in the construction of their men-of-war, and Russia and Japan have followed the example. Large quantities of the material have already been used. In 1883 the orders from the French Navy amounted to 10,000 kg.; in 1884, 190,000 kg.; in 1885, 40,000 kg.; in 1886, 165,000 kg.; and in 1887, 74,000 kg. Since 1886, 165,000 tons (long) have been used. The Amiral Cecille, 5766 tons, carries 40,000 kg.; the Tage, 73,000 kg.; and the Surcouf, 26,000 kg. According to a statement of the factory officials, the French Navy has ordered and actually used 700,000 kg., Russia 80,000 kg., and Japan 225,000 kg. It is also reported that the Italians, Spanish, Greeks, and Danes are using cellulose in the construction of their ships now building.
Inspection.—The test of the cellulose for the navy consists of its inspection with regard to color, specific gravity, and particularly its capacity for absorbing water. Concerning the last, the test is conducted in this way: A chest shaped receiver about 8 or 10 inches long is filled with cellulose. In the top of the chest is a hole 2 inches in diameter, covered by a fine machine-made sieve of twisted brass wire. The chest is suspended from a scale and submerged in water to a depth of 10 feet, and left there until it is known how much water is taken up in a certain time. The specification requires that not more than 13 pounds shall be absorbed in 10 hours, or 22 pounds in 18 hours. The increase in weight is read off directly from the scale.
Firing Trial.—At Toulon a 27-cm. projectile was fired through a belt of cellulose. Only 14 or 15 liters flowed through the shot-hole, and most of this came through immediately after the shot; after a little while the flow ceased entirely.
The Factory Test.—To demonstrate the quickness with which cellulose acts in stopping a leak, the following experiment was made at the factory:
A wooden cask divided into two parts by a thin white tin partition, is filled with cellulose to the required thickness of .125 m. The cask is intended to represent a portion of the ship's belt, and is placed in a second and larger cask, the space between the two serving as a water-chamber. The joints were all screwed firmly together and made perfectly water-tight. A rubber funnel with a stop-cock is fitted on top of the chamber and connected with a reservoir by a rubber pipe 2.8 inches in diameter. When the cock is opened the water-chamber is in direct communication with the reservoir, which being 5 feet above the cellulose, an adequate water-pressure is easily obtained.
The object was to prove the small quantity of water that would be admitted into a ship by the penetration of the belt by a 15-cm. projectile. The flight of the shot was imitated in the following manner:
A wooden model of a 15-cm. shell was secured on an iron rod .8 inch in diameter. The rod was shoved through the cellulose, and the wooden shot adjusted on the rod at a distance of 7.87 inches from the box containing it. A chain fitted with a slip-hook was shackled to one end of the rod, and at the other end of the rod was fastened another chain which led over a pulley and made fast to a weight of 3740 pounds. When the slip-hook was let go, the weight dropped 16 ½ feet, drawing the rod, together with the wooden shot, through the cellulose. Five or six liters of water entered the cellulose at once, but the flow rapidly decreased, and in a quarter of an hour only one to one and a half liters per minute came in. This remained constant for two hours. The opening in the side of the box was then plugged with cellulose, and no more water entered.
The value of amorphous cellulose as a leak-stopping material thus seems to be demonstrated, and its small sp. gr. and cheapness are further advantages in its favor.
In conclusion it may be added that cellulose has been found to be a good excitant in an electric cell. In the factory at Chamalieres elements of this kind are prepared. In a small cell containing the copper and zinc plates is placed cellulose, over which is poured dilute sulphuric acid. A battery of this kind is said to have run a year and given very little trouble.
GRAYDON TORPEDO THROWER.
Under the above heading we have drawings and descriptions of a number of Mr. Graydon’s alleged inventions.
In the description of these inventions the following gives us the keynote of his plan: “The only pneumatic gun for military and naval purposes, designed to throw torpedoes of dynamite or other high explosives, heretofore brought to the 'attention of the Government, is that known as the ‘Zalinski gun.’ Its operations have been attended with varying degrees of success, but its promoters have by no means solved the problem.” With this as a text lie expands his system. Knowing that it would be an advantage to shorten the gun, he makes his gun one-half the length of the Zalinski gun and greatly increases the air pressure. He claims to be able to do this with perfect safety, “owing to the peculiar system of handling the high explosives and charging the torpedoes so as to render premature explosion in the impulse tube or elsewhere impossible from any cause." There can be no doubt that Captain Zalinski has thoroughly understood the advantages of short guns and high pressure, and has only adopted the length and pressure of his system after many experiments. We know his system to be safe. Mr. Graydon claims much, but has no results to back his claim. If his peculiar system of the high explosives and charging the torpedoes renders premature explosion impossible from any cause, why does he adopt air pressures limited by the power of the air compressors? Why not adopt gunpowder and throw his projectile from a modern high-power gun? He claims an extreme range of three miles and may be able to attain it, still it is doubtful if this is any great gain over the Zalinski gun for naval purposes. The latter has a range of about one mile, and the opening range for the present powder guns fired from ships against ships is laid down at 2000 yards, as at this point the target will probably catch one-fourth of the shots fired. It is not probable that the aerial torpedo thrower, supplied with comparatively few projectiles, can open at a longer range with advantage. Many objections are urged against the Zalinski electric fuze, and Mr. Gravdon claims to have a perfect electric fuze. Captain Zalinski’s fuze has proved a success in numerous trials, Mr. Graydon’s may do the same. Another point: “The rigid tail-piece employed in the Zalinski projectiles is an ungainly and cumbersome affair. The Graydon torpedo has a flexible telescopic kite-tail attachment which takes up no storage room, so necessary to economize in all cases; while it performs the part of guide and balance.” If the telescopic kite-tail will serve as a guide and balance it will be a gain over the rigid tail-piece, but knowing the difficulty experienced in the trials with the Zalinski projectile, owing to the insecure fastening of some of the vanes, it is doubtful whether the flexible telescopic tail will stand the test, particularly when higher velocities are attempted. There are several other drawings and descriptions of revolving torpedo throwers, dynamite canister, shrapnel and grape that may or may not prove useful if ever brought to the test of a trial.
The fact is, Mr. Graydon has taken the Zalinski system and noticed points where he thinks it would be an advantage if the system could be improved, and has then very ingeniously worked out these improvements on paper. The Zalinski gun has been tested and has received favorable reports: we have yet to bear of any trial of the Graydon torpedo thrower. Certainly it is difficult to believe that the military and naval officers of the United States are as credulous as this pamphlet states: “Three-fourths of the military and naval officers of the United States and of foreign powers approve the two chief inventions of Lieutenant Graydon, viz., the aerial torpedo thrower herein described, and also his system of firing high explosives from powder guns, as artillery practice proper.” R. W.
INDORSEMENT OF THE HONORABLE SECRETARY OF THE NAVY ON THE REPORT OF BOARD ON TRIAL OF DYNAMITE GUN.*
Navy Department, Washington, February 21, 1889.
The tests for accuracy of the pneumatic dynamite gun, the result of which is recorded in the within report, are satisfactory to the Department, and notice may be given to the company to that effect. The substance of the report is that, taking as a target a space upon the surface of the water 50 by 150 feet (which is considerably less than would be occupied by an ordinary vessel of war), and marking out by buoys one such target at 360 yards, another at 1700 yards, and a third at 2100 yards from the muzzle of the gun, the points being selected by range shots, the pneumatic power worked with such accuracy that more than one-half of the projectiles fired at the respective ranges fell within the target in each case. These results are more than satisfactory. The effective range of the guns is also shown to be largely in excess of the requirements of the statute and contract. The law provided for dynamite guns “of a 10½-inch caliber, and guaranteed to throw shells containing 200 pounds of dynamite or other high explosive at least one mile.” The company constructed the guns of 15-inch caliber instead 10½ without additional expense to the Government, and this report records the fact that—
The twenty-second shot is notable as showing the range of the 15-inch projectile carrying 500 pounds of high explosive to be practically beyond a mile, as the loss of a few more pounds of pressure would certainly have carried it over the 16 yards by which it fell short of that distance.
In another portion of the report, referring to the explosion of a projectile containing 500 pounds of dynamite, it says:
The crater formed by the explosion of this shell was, as may be seen from the photograph, something unusually fine even in the eyes of those accustomed to torpedo explosions. In this connection it may be well to note that no such mass of explosive has ever before been fired from a gun of any description.
A 220-pound projectile was thrown a distance of about miles. Minor defects in the working of the mechanism of a new weapon, such as this is, are to be expected until by practice and experiment details shall in all respects have been perfected. The general results of these experiments must be deemed to mark a notable event in the progress of the arts with which this Department is concerned.
Very respectfully,
W. C. Whitney,
Secretary of the Navy.
NAVAL GEOGRAPHY.
It is the purpose of this article to suggest the collation of certain classes of facts possessing a naval bearing, hitherto treated of irregularly, separately, or else altogether overlooked, into a separate branch of study, and to advocate the incorporation of the same into the elementary naval curriculum, as a sub branch of some existing department thereof. These facts, important in geographical, commercial and military senses, would, when arranged in accordance with a certain scheme, constitute the data for the study of Naval Geography.
Our geographies are faulty. They give but little evidence of any systematic effort towards the classification, in accordance with any scheme of relative importance, of the various towns and seaports set down upon their maps. Centers of activity, agricultural, mining and commercial, are often barely noted—sometimes altogether overlooked—while places that in the past may have played some momentarily significant role are yet presented in their original magnitude. How many of them make any particular mention of Chemul-p'ho, now the chief outlet of Korea, whose development is rapidly leading to the shifting of a national trade from a caravan route to China to an open road abroad by sea? How many point out that as many tons of merchandise now pass yearly through the Sault Sainte Marie as through the Suez Canal?
Again, geographical study should have to the naval student a peculiar signification and bearing. Others view the sea from the land; he is to view the land from the sea. Being attached to the executive branch of the Government, the changes of the present are of more importance to him than the distributions of the past. It is with the aim of increasing his knowledge of the element upon which he is to serve, and of bringing up to date the knowledge that he may already possess, that the following classification of subjects, to be treated under the heading above given, is made.
1. The Geography of the Seas.—A general description of the oceans, of their deep and shallow areas, their islands and archipelagoes, the natural position, character and structure of their dangers. A simple arrangement and classification of the great and well-defined currents, and the winds that are subject to known laws of variation, with their prevailing directions at certain seasons of the year. The close study of the cyclone, however, is not here intended, as it involves the question of the handling of the ship, and could therefore be more properly discussed under the heading of Seamanship. A sketch of the ocean coast-lines, with the distribution of harbors as to character and frequency; also, a description of the tidal movement along them, and a mention of those shorelines and areas that are as yet unsurveyed, or but partially surveyed.
2. The Principal Steam and Sail Commercial Routes. —In direct ratio with the development of the ship and the advance in meteorological knowledge, the certainty of navigation and the definiteness of the sea-route have been increased. It has become possible to create ocean lanes for purposes of safety; a regular variation in path, in accordance with the seasons of the year, may be observed for vessels navigating the waters of the temperate zone, while in tropical waters the routes taken by successive steamers from port to port are in many cases nearly identical at all times.
The more certain knowledge of the winds of the globe has also led to increased regularity in the movement of sailing craft, and has brought about not only a reduction of traversed area, but also an actual shortening of time of passage. Of this the work of Maury, who, from the comparative study of data obtained from the logs of a large number of sailing vessels running from New York to the equator, succeeded in mapping out a route by the following of which the average time of passage could be reduced ten days, is a brilliant example.
3. The Great Trades of the World.—The transfer of staple commodities across the ocean is in accordance with general laws governing time of shipment, production, and direction of movement. The student should know something of our own foreign commerce, of its nature and distribution, and of those of our own products upon which other countries are more or less dependent for support.
4. Naval Forts, Colonies, and Coaling Stations.—The chief commercial ports and naval stations of the world are centers of financial, engineering and military enterprise, and as such are of especial interest to the naval student. Short descriptions of these, with notes as to size, character and extent of harbor, should be given. Special attention should be paid to those of our own country.
The colonial possessions of other countries; their relations, political and commercial, with the mother country. The position and importance of coaling stations. It may be well to add that under this head no more than a brief statement of facts would be made, the discussion of strategic questions belonging elsewhere, and for minds more mature than those for whom this elementary collection of data would be intended.
5. Communications.—A brief description and enumeration of the chief transoceanic steamer lines, especially those that carry the mails, and those that are under government subsidy, giving their itineraries. Notes on the world's network of telegraphic cables, on the general character of cable landings, and on proposed extensions of the system.
6. Meteorology.—The advances that have recently been made in meteorological science. The system of simultaneous international meteorological observations. Maury's weather charts. The "square" system. Recent U. S. naval meteorological work. The North Atlantic pilot chart. Systems of coast signal stations and weather forecasts. Meteorological instruments in practical use afloat. Employment of the same. Errors to be avoided in observation.
The above is a brief resume of the subjects to be included under the head of Naval Geography. Should the study ever be developed, it is very probable that its scope would be modified, and the matter herein not dwelt upon would be taken up.
Any departure from existing methods becomes doubly worthy of consideration when it has met with the approval of those in authority. It happens that in this case not only has approval been given, but that a step towards the establishment of such a course has, in one country at least, been made. Among the programs of subjects studied at the Russian Naval School in 1887-8 was one entitled "Statistics and Geography of the Seas," of which I here give a rough translation.
Statistics and Geography of the Seas.
Definition of statistics. Development of statistics. Relation of statistics to geography and history. Statistical fact. Methods of representing statistical facts, arithmetical and graphical. Statistical institutions, temporary and permanent. Definition of empire. End of empire.
Territory.—Importance of territorial relation. Meaning of the development of boundary. Relation of boundary to area in Russia and in other first-class European empires. Peculiarities of movement of trade for ports of the Baltic, Black, Azov and White Seas. Peculiarities and particulars of the water boundaries of Russia. Statistical review of Russia, orographic and hydrographic. Influence of extent on the welfare of the Empire. Influence of the extent of Russia on its political and economical relations. Influence of soil and climate on the welfare of its inhabitants. Soil of Russia; climate of Russia; distribution of atmospheric precipitation.
Population.—Theory of Malthus. Movement of population; classification of population by sex and age; births, deaths, causes influencing death, natural causes; climate and soil in relation to age; disease; means of existence; kinds of occupations; acclimatization; enumeration of population.
Popular Activity.—Conceptions of needs, utilities and values. Labor and its role. Capital and its role. Savings banks; insurance companies. Union of capital (shares, obligations, dividends). Agricultural system in Russia, and special features thereof. Products of Russia: breadstuffs, beet-root, potatoes. Horticultural gardening, forestry, raising of cattle.
Geography of the Seas.—Great or Pacific Ocean. Position, size, importance in the world's trade. Time required to cross. Sea, gulfs and straits. Change of name on coast of Asia, America. Inhabitants. Foreign and native populations. Notes on docks, dock-yards, trade centers, coal deposits and other belongings. Telegraphs and commerce. Ocean cables.
Such is the scope of one branch of Russian naval education, one to which we can offer in our system no parallel. In some respects there is none needed, the generalities of the Malthusian doctrine, and the relations, social and political, of the members of an empire to one another, being of no importance to us. In others this program would seem well worthy of attention, as it bears witness to an effort to place before the student matter of professional importance which is of a nature closely in keeping with the progress of the day, and which is not treated of in any other department of professional study.
Should it be deemed advisable at any future time to develop this subject, an elementary text-book could easily be compiled from the sources of information now available to the Office of Naval Intelligence.
J. B. Bernardou, Ensign, U. S. Navy.
KRUPP’S TRIALS OF A NEW POWDER.
[Deutsche Heeres-Zeitung, February 9, 1889.]
ICrupp’s last report, No. 73, October, 1888, gives a very important account of experiments with a new powder manufactured by the United Rheinisch-Westphalian Powder Co.” According to the report, the brown prismatic of this company has been as successful as that of the Rottweil-Hamburg Factory, without an important increase of pressure.
After long trials the United Rheinisch-Westphalian Company has succeeded in introducing a new powder, which not only does more work than the earlier powders, with less pressure, but which also possesses the property o£ evolving much less smoke, a result which has been desired for a long time.
Krupp has at last given to the public the result of the trials with this powder, and the information merits the closest attention of the military world.
There are two grades of the new powder, namely: 1, Rough granulated gunpowder C/86, for use in the small calibers (4 cm. to 8.7 cm.), and 2d, prismatic powder C/86, at present used and treated in the medium calibers (10.5 cm. to 25 cm.).
The first kind, the rough granulated powder, corresponds pretty closely in form, coarseness of granulation and color with field cannon powder in use until recently, but differs in composition. The advantages claimed are, 1st, greater efficiency per kilogram; 2d, easier recoil; 3d, less and thinner smoke, disappearing more rapidly, thereby interfering less with sighting; and 4th, less flame.
On the other hand, the new powder has the disadvantage of being much more hygroscopic than the olef. Uut, since it is necessary to pack even the old powder in air-tight cases to preserve its efficiency during long stowage, this objection is not so great as it would be if the powder were stowed in kegs. In order to preserve this powder in cartridges during transportation in the field, metallic cases, such as were used during the experiments, will probably have to be used.
The trials of the powder showed, 1st, the increase of efficiency per kilo, as compared with the old; 2d, the proportion of the increase of efficiency; and 3d, the loss of efficiency due to long stowage.
The following table shows a summary of the experiments:
[TABLE]
From these results it follows that the new powder G. G. P. C/86 is about 1¼ or 1 1/3 times more efficient than the old, and that for the same velocities only ¾ of the amount used in the old charge is required.
The following table exhibits the evenness of performance of the new powder:
[TABLE]
As the powder has already been stowed two years in the magazine, an opinion may be formed from the experiment of its keeping qualities.
We give here only some of the results lying farthest apart, and therefore showing proportionately the greatest differences.
[TABLE]
These firings, besides others given in the report, show that the new powder docs not lose more in velocity than the old rough granulated powder.
The new prismatic powder of 10-15 cm. (P.P. C/86 / 10-15 cm. )was tested in the 10.5 cm. of 35 cals., 15-cm. gun of 25 cals., and the 15-cm. siege guns of 28 and 30 cals., and gave results equal to the old prismatic powder, P. P. C. 82 / 10-15 cm.
It is sufficient to quote here some of the results obtained from the two powders in these guns.
[TABLE]
The above tables, and almost all the rest of the data contained in the report, show, 1st. That the efficiency of the new prismatic C/86 is really greater per kilo, than the old C.82. 2d. That the powder C.86 gives the same initial velocity with less pressure than the old C.82. 3d. That with C/86 a velocity can be obtained without exceeding the allowable pressure that C/82 cannot give.
While the United Rhcenisch-Westphalian Company are to be congratulated on their success, the country is scarcely in a condition to profit by their rapid advances in powder-making, as the magazines are at present filled with the old powder. A. G.
THE GUN OF THE AMIRAL DUPERRÉ.
[Translated from the Deutsche Heeres-Zeitung.]
The terrible accident on board the Amiral Duperré is still fresh in the public mind. On the 12th of last December the 34-cm. (13.4-inch) gun in the afterturret of this ship was burst by the ordinary service charge of powder. The breech of the gun was blown overboard after it had penetrated the shield which protects the crew from shots from the rapid-fire and revolving guns. An officer, sub-officer, the chief mate, and three seamen gunners were killed.
As this is the first serious accident to our ordnance since the introduction of steel guns in the fleet, all possible theories have been advanced to explain the cause. Instead of giving ourselves up to such speculations, it seems wiser to await the official reports, which will not be published until a thorough examination has been made of the gun and powder. A brief description of the gun, however, will be appropriate.
The gun is of the model of 1875, and was one of the first of the new steel construction introduced in the French Navy. It was entirely of steel, strengthened on the outside by hoops, and on the inside by a tube extending as far as the screw-box. The charge was 258 pounds W. 30/38 powder, the projectile weighed 726 pounds, and was a steel shell. The initial velocity was 1595 f. s. It will be well to remember these figures.
The ordnance of 1875 was antagonized by many of the best naval artillery officers, and was bitterly opposed by the distinguished and lamented General Frebault, The Ruelle Foundry at this time guaranteed every security for cast-iron, but steel, on account of its lesser weight and other good qualities, had warm advocates in naval councils, and finally won the victory. Cast-iron was banished from the coast defense, and steel was exclusively used for naval guns. The model of 1875, however, was not perfect, and artillerists and metallurgists set to work, the former to improve the methods of gun construction, the latter to improve the metal, and with such success that the guns and the steel of to-day are vastly superior to the model of 1875. Besides, trials on the proving ground at Gavres had shown the advantage of a few changes in the old model, and of strengthening the gun by the introduction of a tube the entire length. The changes were adopted for the guns then in course of construction, but as, since the arming of the fleet with these guns, no accident had happened, it was not deemed necessary to strengthen the guns already afloat. Time passed, and a new factor entered into the question; the rough granulated powder which had been used in former years was displaced by the brown prismatic powder of hexagonal prisms. This powder, commonly known as cocoa powder, burnt slower, strained the gun less than the granulated powder, and imparted a higher initial velocity to the projectile. After long trials it was introduced in the service. The gases evolved from this powder produced an immense pressure in the chamber and bore of the gun, but it had been proved by experiment that a heavy, well-constructed gun easily endures a chamber pressure of 16 tons to the square inch. Considering this fact, and after a number of firings, it was concluded that a charge of 304 pounds of brown powder, P. B S., did not strain the 34-cm. gun as much as 258 pounds of W. 30/38. With the former charge an initial velocity of 1S23.6 f. s. was obtained instead of 1595 f. s., and consequently the gun had greater range and deeper penetration. As is well known, it was the use of this charge of 304 pounds that burst the gun.
It will be seen from what has been said that the accident is attributable to one of three causes: the metal, the construction, or the powder. Previous trials at Toulon have demonstrated that the metal was perfectly sound; although infinitely better steel is produced to-day, this showed neither flaws nor blisters. Concerning the construction, a careful examination of the other guns of this model have shown them to be in excellent condition. But as recent guns are far superior to those built in 1875, anc' such great progress has been made in construction by the employment of separate parts, no one can affirm that the model of 1875 was free from danger.
The question of powder remains to be considered. Brown powder has been in use a comparatively short time, and although it was tested before issue with the greatest care and caution, that on board the Amiral Duperré was found to be in an especially peculiar condition. The temperature in the magazines where the powder was stowed was found to rise at times as high as 127° F. The powder thus exposed to an abnormal drying process would naturally burn quicker than any one could foresee, and the great pressure it developed when fired was sufficient to burst the gun.
In order to avoid accidents in future, it is only necessary to reduce the charge, and this has been done already. Admiral Krantz has ordered that hereafter the charge shall be calculated with reference, not to the pressure, but to the initial velocity of 1595 f. s., which had been fixed originally for the 34-cm. gun of the model 1875. I" this way the advantages of brown powder will be obtained by relieving the strains in the bore rather than by improving the ballistic qualities of the gun. It has also been ordered that the magazines of ships shall be better isolated, in order to avoid the excessive rise of temperature which was observed on board the Amiral Duperré.
Conclusions.—It can be assumed that the catastrophe which we have to deplore was purely accidental, and that the quality of the steel should not be questioned, as the metal does not appear to have been in fault. Finally, we maintain that it is good to repeat our assertion that the later models are immeasurably superior to the original construction; that since 1875 great advances have been made in the fabrication of guns; and that all accidents can be avoided by not straining the gun to its utmost limits of endurance.
We have just passed through a period which favored the dangerous maxim to “claim for every war-engine the highest efficiency.” As a consequence of this erroneous demand, accidents without number have occurred in France and other countries to ships and engines of light build. A reaction has justly set in against this system, the dangers of which we have from time to time pointed out, and it is to be hoped, in the interest of our finance and naval material, that we will not have a repetition of a doctrine which has been attended by such disastrous results. A. G.
SEAMLESS TUBES FOR GUN-MAKING.
Another advocate of mild steel, William Henry Browne, has brought forward a method of building up modern high-power guns. This is done under his patents for drawing seamless tubes from boiler plates. “A circular piece of mild steel boiler plate is rolled until it is certain there are no cavities in it (?). The plate is one-half inch in thickness, and is pushed through dies by means of hydraulic pressure. This dishes up the sides of the plate until it resembles a saucer. The process is repeated until a tube of the required diameter and about one and one-eighth inches in thickness is formed. The sides are absolutely uniform in thickness. The bottom is then cut off, and similar shells or tubes of larger diameter are formed about the core. These form the barrel of the gun, and the shells are so closely united that layers cannot be detected when the ends are turned in a lathe. Shorter tubes are added to reinforce the butt of the gun.”*
He claims that the finished tubes have stood the test of 100,000 pounds to the square inch when made of plate of 60,000 pounds tensile strength. He says: “The shells are necessarily true inside and out, and by being passed through the dies cold a few times become hardened. This is where the tensile strength is increased.”
It seems as if too,000 pounds tensile were rather high for mild steel, and that drawing cold might cause a cold flow of metal that would leave injurious strains and stresses. This is but another form of a built-up gun, using milder steel than that ordinarily used. By a greater amount of work he may be able to produce the same tensile strength as in the ordnance steel, without destroying the elongation, etc., and his process may have the advantage of being cheaper. The trouble generally with the advocates of new methods of gun-making is that they assume they can produce the same effects with large masses as with small, and in this they almost invariably fail. There is one great advantage of this method over that of casting. You should be able to tell from the tubes the class of gun you were getting, and not be troubled with hidden defects, as in casting. Again, if one good gun was produced, there should be no difficulty in producing any number; whereas, even if one good cast-steel gun could be produced, there would be no certainty that the man who made the cast might not fail in making others, and a great uncertainty as to whether others could cast successfully by the same method. The advocates of cast-steel guns expect to produce the effects of work in the metal without the trouble and expense of working it, and by using masses of metal of low tensile strength to make a gun that will stand high strains. This they will do when the perpetual motion machine is invented. The method of gun-making under consideration has the advantage of proposing to work the metal, the question being if it can be done cheaply and produce the effects as claimed. R. W.
* Secreted by leaves of Copernicia cerifera.—W.
* Army and Navy Register, March 2, 1889.
* The Evening Journal, Jersey City, N. J,