NOTES ON THE LITERATURE OF EXPLOSIVES.*
No. XXVII.
The “19th Annual Report of H. M. Inspector of Explosives” for the year 1894 states that blasting amberite, cordite, collodion cotton, Westfalite and Von Forster’s powder were added to the list of authorized explosives; seeurite, compressed securite and Denaby powder were dropped from the list, as their manufacture was given up during the year. Nitro paper, plastomentite, electronite, granulite, normal smokeless powder, one variety of Rosslyn smokeless powder, emerald powder, carbonite, smokeless powder and Coopal’s powder successfully passed Dr. Dupré’s tests and were favorably reported on. Britianite passed the preliminary tests. Schnebelite, three varieties of Rosslvn smokeless powder and one of electronite failed and were rejected.
Schnebelite offers another example of the eventual rejection of a chlorate powder, the powder having passed successfully the preliminary trials as reported December 13th, 1893. During the succeeding year it was submitted to a more prolonged and searching examination, in the course of which, like other chlorate mixtures before tested, it developed certain features pointing to danger. Not only did it show a marked increase in sensibility to percussion and friction, but an appreciable portion of the chlorate became reduced to chloride.
The sample of electronite which failed showed the peculiar behavior of ammonium salts. This sample consisted of amberite No. 1 (nitro-cellulose, nitro-glycerin, paraffin and shellac) mixed with a considerable proportion of ammonium carbonate, and it suffered serious decomposition, even when kept at ordinary temperature.
An invention having for its object the prevention of the mercury fulminate from escaping from detonators, and which consists either in covering the fulminate with a solid disk of celluloid which fits tightly in the case, or in coating the fulminate with collodion, was reported upon favorably, as was an invention consisting in the introduction of glass tubes filled with a strong solution of ammonia into gunpowder blasting cartridges, with a view to diminishing the effect of the flame produced on firing them.
With the admission of collodion cotton to the “authorized list,” a revision in the definition of terms has been made. Hence officially collodion cotton consists “of thoroughly purified nitro- cotton (a) of which not less than 15 per cent, is soluble in ether- alcohol, and (b) which contains not more than 12.3 per cent, of nitrogen,” while gun-cotton consists “of thoroughly purified nitro-cotton (a) of which not more than 15 per cent, is soluble in ether-alcohol, or (b) which contains more than 12.3 per cent, of nitrogen; and with or without carbonate of calcium.” The term nitro-cotton is to be “substituted for nitro-cellulose in the definitions of ballistite, gelatine dynamite, blasting gelatine,” etc. It is to be regretted that strictly scientific terms were not adopted at the outset, since much confusion of ideas has resulted from the official classification.
Another new feature in designation is in the use of the terms “percussion cap” and “detonator,” as a consequence of the two similar accidents which occurred in the drumming of caps in the Royal Laboratory, Woolwich, on July 24th and August 20th. The drum in which the caps are cleaned is of sheet iron, 2 feet in diameter by 7 inches wide, and at the time of the explosion it was charged with 80,000 caps for the 0.303-in. ball cordite ammunition, each containing 0.4 grain of a composition consisting of mercury fulminate, 6 parts; potassium chlorate, 14 parts; antimony sulphide, 18 parts; powder, mealed, 1 part; sulphur, ground, 1 part; together with a quantity of clean sawdust. The drum, which is turned by hand, had been revolving some three or four minutes when the explosion took place. The explosion partly blew out one side of the drum and scorched the rope mantlet which surrounds it to a height of 6 feet 6 inches, doing no further damage. About 20,000 caps were recovered unexploded. Experiments made to determine the liability of these caps to explode cn masse showed that this would not occur unless the caps were raised to a high temperature or mixed with loose composition, but as an additional precaution the dividing line between percussion caps and detonators has been raised above that fixed in Annual Report, 1885, pp. 69, 117, and 1890, p. 53, so that now it is ordered that “a percussion cap to be one containing a charge not exceeding 0.5 grain of composition, or 0.6 grain of composition when the quantity of fulminate of mercury does not exceed one-fourth of such composition; in any other case the cap will rank as a detonator.”
In order to identify individual cartridges of explosives, especially when stolen, the German and Belgium governments have recently required that each be marked and numbered. The ingenious method devised by Germany, through which is indicated the factory of origin, date of manufacture, and case in which packed, is described in this report at length with diagrams. After consultation with English manufacturers it was decided that in view of the expense and inconvenience the system entails, and the facility with which the elaborate and costly precautions could apparently be defeated by evil-disposed persons, there was not sufficient warrant for directing the compulsory adoption of such a system.
The comments of Dr. Dupré on an accident at Gover Farm, Abergele, during the burning of rubbish in a grate, illustrates how numerous the causes are which may possibly give rise to explosions. He says: “I have carefully read the further information given, and have also inquired as to what kind of material farmers use that might possibly cause an explosion. I find that some kinds of manures are used consisting of a mixture of saltpeter and ground linseed, or similar cake. As a rule, no doubt, the saltpeter would not be present in sufficiently large proportion to produce an explosion, but it is quite possible that some sample of such manure may have accidentally been mixed with a larger proportion of niter than usual and thus have caused the accident.
It is also possible that the farmer intended to mix a small quantity of manure himself and bought the niter for the purpose.”
The repeated spontaneous explosion of fireworks containing sulphur in admixture with potassium chlorate or other chlorate has led to the issuing of an Order in Council prohibiting the manufacture, importation, storage, conveyance or sale of such fireworks. An explosion of some colored lights at Hatton Garden, June 16, appears to have been due to the simple contact of the mixture of barium chlorate and shellac with the gunpowder in the quick-match. Notwithstanding they had been exposed, between two and three years, against the south wall to all weathers, they suddenly took fire. The case bears a strong resemblance to that occurring in the ignition of some green lances at Messrs. Pain’s factory, in 1890, and which was clearly shown to be due to the contact of a composition containing barium chlorate with one containing sulphur.*
In recording with their usual fullness the foreign explosions of the year, considerable space is given to the accidents occurring in the United States on July 4th, which closes with the following amusing remark, “'Thanksgiving Day' therefore appears to have proved more than usually costly in 1894.”
The importation of foreign nitro-glycerin compounds continues to decrease, it having fallen from 1,325,950 lbs. in 1889, the highest mark reached, to 539,802.5 lbs. in 1894, while the importation of detonators increased to 9,765,400 for the year. There were 290 tons of fireworks imported in 1894 against 190 tons in 1893.
It is to be noted that the samples of blasting gelatine tested failed to withstand the test as they should.
In Dingier’s Polyt. Jour., 284, 137-143; 1892, O. Muhlhauser gives the result of his studies on the “Higher Nitric Ethers of Starch.” After reviewing the history of the discovery and work done on nitro-starch, he says that it is only recently, by means of a process devised by the “Actiengesellschaft Dynamit Nobel,” that it has been possible to manufacture it economically, and thus make it available as an explosive for military purposes. The product prepared by this process has the following composition: C6HsO8(NO3)2.
The author succeeded in preparing two bodies of the composition C6H7½, O2½ , (NO3)2½ , and C6H7O4(NO3)3. The starch molecule must consequently be taken twice as large, viz. C12H20O10, and the higher members regarded as—
Per Cent. N.
Tetra-nitro-starch, C12H10O6(ONO2)4............. 11.11
Penta-nitro-starch, C12H18O8(ONO2)5............. 12.75
Hexa-nitro-starch, C12H14O4(ONO2)6............. 14.14
That no nitro-compounds, but true ethers (esters) of nitric acid are formed, is proved:
1st. In that the substances on treatment with sulphuric acid, separate NO3H. The O.NO2 residue appears thus to be replaced by the sulphuric acid residue.
2nd. On treatment with aqueous ferrous chloride, nitric oxide and soluble starch are regenerated.
3rd. On shaking with sulphuric acid over mercury all nitrogen is split off in the form of NO.
The body prepared by the process above referred to will be taken as tetra-nitro-starch.
This process is carried out as follows: Potato starch is dried at 100°, then ground and dissolved in nitric acid of 1.501 sp. gr. in a suitable vessel made of lead and provided with two jackets cooled by water. A screw agitator causes the acid to circulate. The starch is introduced through an opening in the cover of the combined agitator and digestor in the proportion of 10 kilos of starch to 100 kilos of acid, the temperature being maintained between 20° and 25°.
This solution is then led to a precipitating apparatus, which is also surrounded with a cooling jacket and provided with a double perforated bottom, between which is placed gun-cotton to act as a filter. This vessel is filled with spent nitro-sulphuric acid from the nitro-glycerin manufacture, and the solution of starch in nitric acid is sprayed into it through an ejector worked by compressed air, whereby the nitro-starch is precipitated in the form of a fine-grained powder. 500 kilos of spent nitro-sulphuric acid are required to precipitate 100 kilos of starch solution.
The nitro-starch collects on the gun-cotton filter, when the acid solution is run out and drained off through the tap at the bottom of the vessel and below the filter. It is then further freed from acid by pressure and washing till a neutral reaction is attained, and afterwards it is treated and let stand for 24 hours in contact with 5 per cent, soda solution. The product is then ground until a “milk” is formed, which is filter-pressed and washed with water, and lastly treated with a solution of aniline, so that the pressed cake, which contains about 33 per cent, of water, shall contain 1 per cent, of aniline.
Nitro-starch prepared by the author on the same lines in the laboratory contained 10.96 and 11.09 per cent, of N. It is a snow-white powder, which becomes electrified on rubbing, and is very stable and soluble even in the cold, in nitro-glycerin.
The author also prepared a tetra-nitro-starch containing 10.58 and 10.50 per cent, of nitrogen by pouring into water a solution of starch in nitric acid, which had stood for several days. The body thus produced had all the properties of that prepared by the other process.
Penta-nitro-starch is produced along with some tetra-nitro- starch by adding 20 grms. of rice starch dried at 100 to a mixture of 100 grms. of nitric acid sp. gr. 1.501, and 300 grms. sulphuric acid sp. gr. 1.8. After standing for one hour the mass is discharged into a large quantity of water, and then washed with water and soda solution. The yield was 147.5 Per cent. This body was heated with ether alcohol, then the ether was distilled off; the penta-nitro-starch thus became precipitated, the tetra- compound remaining dissolved in the alcohol. The portion insoluble in alcohol contained 12.76 and 12.98 per cent, of nitrogen, and was thus penta-nitro-starch. The other portion contained 10.45 °f nitrogen.
Hexa-nitro-starch is the chief product when 40 grms. of dry starch are treated with 400 grms. of nitric acid, sp. gr. 1.501, and allowed to stand for 24 hours, and then 220 grms. of this solution are poured into 600 cc. of sulphuric acid of 66° B. The white powder thus produced contained 13.52, 13.23 and 13.22 per cent, of nitrogen, and therefore consisted principally of penta- and hexa-nitro-starch.
The experiments showed that the bodies prepared by precipitating the nitro-starch by strong sulphuric acid were less stable than those precipitated by water or weak sulphuric acid, the author being of opinion that possibly in the former case a sulpho- group may be formed, which in small quantity might occasion this instability. The following table shows the behavior of bodies prepared in different ways under various conditions.
| Ignition Pont C. | Stability. | Per cent. N. | 96 per cent. Alcohol. | Ether. | Ether Alcohol. | Acetic Ether. |
1 part nitric, 2 parts sulphuric acid (containing 70 per cent, of water)........ | 175° | Stable. | 11.02 | Soluble. | Insoluble. | Soluble. | Soluble. |
1 part nitric acid, water | 170° | Stable. | 10.54 | Soluble. | Insoluble. | Soluble. | Soluble. |
1 part nitric acid, 3 parts concen- trated sulphuric acid.............................. | 152° | Unstable. | 12.87 | Insoluble. | Insoluble. | Soluble. | Soluble. |
1 part nitric acid, 3.5 parts concentrated sulphuric acid | 121° | Unstable. | 12.50 | Insoluble. | Insoluble. | Soluble. | Soluble. |
1 part nitric acid, 3 parts concentrated sulphuric acid | 155° | Unstable. | 13.53 | Insoluble. | Insoluble. | Soluble. | Soluble. |
The author recommends the production of a smokeless powder by moistening 6 grms. of nitro-jute and 2 grms. of nitro-starch with acetic ether, working into a uniform mixture, and then drying at 50°-56°. This product contained 11.54 per cent, of nitrogen and was very stable.
The Jour. American Chemical Society, 18, 819-846; 1896, publishes under the title of “The Development of Smokeless Powders,” the presidential address delivered by Charles E. Munroe, in which, after noting the various inventions and discoveries which made the production of a smokeless powder possible; the improvements in arms and appliances which made a smokeless powder essential; and the composition, properties and methods of manufacture of the various characteristic powders, he says:
“I began my own experiments with smokeless powder manufacture in 1889. At this time the remarkable results published from France and the announcement that that country had adopted a smokeless powder had produced their desired strategic effect. All her rivals were seeking to be equally well equipped, and were hastening to adopt a powder even before its qualities were thoroughly proven. The newspapers contained remarkable accounts of their performances and alleged descriptions of their methods of production which, while interesting as news and conveying valuable suggestions, could not be relied upon as to accuracy in details.
“At the outset, being familiar with the impossibility of securing absolute uniformity and constancy of composition in physical mixtures like gunpowder, and realizing how important this feature was with our precise modern weapons and when employing an explosive possessing great energy, I determined to attempt to produce a powder which should consist of a single substance in a state of chemical purity. This was a thing which I had not known of having been done, nor have I yet learned that any one else has attempted it. Among the bodies at command the nitric ethers seemed most available, and of these cellulose nitrate seemed for many reasons the most promising.
“There are several of these nitrates (authorities differ as to the number) which differ in their action towards solvents, though all, except the most highly nitrated, are soluble in methyl alcohol. In the commercial production of cellulose nitrates certainly, and so far as I have observed under all circumstances, when nitrating cellulose, the product is a mixture of different cellulose nitrates. Even in the perfected Abel process for making military guncotton, as carried out at the Royal Gunpowder Factory at Waltham Abbey, according to Guttman, “Manufacture of Explosives,” 2, 259; 1895, the product contains, as a rule, from 10 to 12 per cent, of nitro-cotton.
“Consequently I began by purifying my dried pulped military gun-cotton, which was done by extracting it with hot methyl alcohol in a continuous extractor, and when this was completed the insoluble cellulose nitrate was again exposed in the drying room. The highly nitrated cellulose was then mixed with a quantity of mono-nitro-benzene, which scarcely affected its appearance and did not alter its powdered form. The powder was then incorporated upon a grinder, by which it was colloidized and converted into a dark translucent mass resembling india rubber. The sheet was now stripped off and cut up into flat grains or strips, or it was pressed through a spaghetti machine and formed into cords, either solid or perforated, of the desired dimensions, which were cut into grains. Then the granulated explosive was immersed in water, boiling under the atmospheric pressure, by which the nitro-benzene was carried off and the cellulose nitrate was indurated so that the mass became light yellow to gray, and as dense and hard as ivory, and it was by this physical change in state, which could be varied within limits by the press, that I modified the material from a brisant rupturing explosive to a slow-burning propellent.
“This is the powder which I styled indurite, and which has been popularly known as the naval smokeless powder.
“I was satisfied that I was justified in starting on this new practice in powder-making when I found, on examination of the samples of foreign military powders which later began to reach me officially, that they were heterogeneous mixtures, as the old gunpowder is, and that they contained matter which was volatile at ordinary temperatures, and when I learned that the nitro- glycerol powders cracked from freezing.
“I was still more satisfied when I learned the results of the proving tests which were all made, except the chemical, stability and breaking-down tests, by naval officers detailed for this purpose at the Proving Ground and elsewhere and who had no prejudice in its favor. All of the numerous publications which have appeared about it have issued from headquarters, and I present the matter myself here for the first time.
“I have appended the data from these trials to this address, where on inspection it will be seen that, after development, the powder in use, in successive rounds, gave remarkably regular pressures and uniform velocities. I was informed by the Chief of the Bureau before the firing trials, recorded in the tables, began, that if I could produce a powder giving 2000 feet initial velocity and but fifteen tons pressure it would be a complete success. Inspection of the tables shows that this was more than realized, and that in two successive rounds in the six-inch rapid- fire gun, using twenty-six pounds of my powder and a 100-lb. projectile, the pressures were 13.96 and 13.93 tons and the velocities 2469 and 2456 feet per second respectively, while, according to the Report of the Secretary of the Navy, 1892, page 26, ‘ The powder manufactured for use in the six-inch rapid-fire guns was stored at Indian Head Proving Ground, through a period of six months, covering a hot summer, and at the end of the time showed no change in a firing test.”
“On page 25 Secretary Tracy says: ‘It became apparent to the Department early in this administration, that unless it was content to fall behind the standard of military and naval progress abroad in respect to powder, it must take some steps to develop and to provide for the manufacture in this country of the new smokeless powder, from which extraordinary results had been obtained in Europe. With this object, negotiations were at first attempted looking to the acquisition of the secret of its composition and manufacture. Finding itself unable to accomplish this, the Department turned its attention to the development of a similar product from independent investigation. The history of these investigations and of the successful work performed in this direction at the torpedo station has been recited in previous reports. It is a gratifying fact to be able to show that what we could not obtain through the assistance of others we succeeded in accomplishing ourselves, and that the results are considerably in advance of those hitherto attained in foreign countries.’
“From this survey we see that all the smokeless powders that have met with acceptance and proved of value as ballistic agents, with the exception of Indurite, are mixtures of one or more of the cellulose nitrates, or mixtures of these bodies with nitro-gly- cerin or some other oxidizing agent, like barium nitrate, and a restrainer or with a nitro-substitution compound, and that all have been condensed or hardened into a rubber-like or celluloidlike form, by which, even under the high pressures which obtain in the gun, they are expected to undergo combustion only, and that at a moderate and regular rate.
“In thus condensing the material and in determining the best form of grain, it will be observed that we have been guided by the experience gained in the compression of gunpowder, and we have been able to effect this as we have by the experience gained in the development of celluloid, and we have been able to manipulate our product and shape it into grains only by adopting the methods and machines developed in the manufacture of food, while we have been able to test our product and check our results, and thus ensure a more rapid and certain advance by the constant use of the pressure gauge and velocimeter. In my opinion, if these resources had not been at command and available the smokeless powder industry would not yet exist.
“From what has been said it may properly be inferred that we seek in these new powders all the virtues of the old gunpowder with the addition that the new powder shall be smokeless, impart higher velocities while producing no greater pressures, and that less of it shall be required to do the work. These requirements may be summed up as follows:
“The conditions that a smokeless powder suitable for a propellent should fulfill are:
“1. That is shall be physically and chemically uniform in composition.
“2. That it shall be stable and permanent under the varying conditions of temperature and humidity incident to service storage and use for all time.
“3. That it shall be sufficiently rigid to resist deformation in transportation and handling.
“4. That it shall produce a higher or as high a velocity with as low a pressure as the service charge of black powder for a given piece.
“5. That it shall be incapable of undergoing a detonating explosion.
“6. That the products of its combustion shall be nearly, if not quite, gaseous, so that there shall be no residue from it and little or no smoke.
“7. That it shall produce no noxious or irrespirable gases or vapors.
“8. That it shall not unduly erode the piece by developing an excessive temperature.
“9. That it shall be as safe as gunpowder in handling and loading.
“10. That it shall be no more than ordinarily dangerous to manufacture.
“Most of these requirements have been satisfied in several of the powders, but time alone can determine the question of absolute stability, and especially as the comparison is instituted with gunpowder, which has been under observation for over 500 years.
“We can and do apply tests whose results give us some confidence, as I did when I exposed indurite wrapped in felt in an iron vessel to a temperature of 208° F. for six hours without its undergoing change, and again at a temperature of 2120 F. for twenty hours before any signs of change were observed, and again to 5° F. without its being affected.
“In fact, from the outset I have advised the most rigid tests being applied, and drew up the following scheme for the Navy Department in July, 1891, by which to test indurite:
“The most important requisite of powder, after passing the proof test, is that it shall retain its characteristics under all the conditions of storage or transportation which may obtain in the service, or that, if any change does take place, it shall not cause the powder to develop under the ‘proof’ conditions any greater pressure than it did at the time of proving, and that such falling off in velocity as may result from this change in the powder shall not be relatively greater than that which obtains for service black powder, and shall be uniform for the same conditions of exposure.
“In providing for this test I would first prove a ten-pound lot to determine the maximum weight that will come within the limits fixed for pressure and velocity, and then I would load 1000 Winchester 30.1 cal. and 1000 Mannlicher shell with a charge some grains (say five) less than the maximum, so as to be doubly safe in case the pressure should become increased through the treatment to which the powder is subjected.
“The loading should be done with extreme care by skilled workmen in an especially clean and uniformly heated and dried room. The charges should be weighed on chemical balances and with all the precautions surrounding an analytical operation. The balls should be weighed and gauged, and the shell should be gauged so as to secure as nearly absolute uniformity as possible, while the caps and priming (if used) and wads should be identical for each shell of each 1000 lot.
“These being prepared, I would pack these ball cartridges precisely as if ready for issue to the service, and then I would store 385 Winchesters and 385 Mannlichers in the regular magazine at the Naval Torpedo Station, and the same number of the same kind in the regular magazine at the Naval Ordnance Proving Ground. I would then draw from the magazine at the Torpedo Station twenty-five Winchesters and twenty-five Mannlichcrs and fire them, using the muskets and measuring instruments which are to be used throughout the trials, and I would repeat this trial every month for three years, firing ten rounds of each form of ammunition and using the same muskets and instruments throughout. At the same time I would have an identical set of tests made at the proving ground, the same precautions being taken there regarding the instruments and tools. Throughout the tests a close watch should be kept on the magazine by means of maximum and minimum thermometers, so that if abnormal results are obtained in firing it may be known whether or not any abnormal conditions have obtained in the magazine. This series of tests will consume 1540 rounds. It would, in my judgment, be of much value to store with these cartridges and fire with them an equal number of charges of standard service black powder, to be used as a standard for reference by which any error in the observations or defects in the instruments may be detected.
“I would take eighty rounds of the Winchesters and eighty of the Mannlichers and place them in an oven heated to 140° F. or thereabouts. At the end of one month twenty of each are to be drawn out, and this to be repeated each month for four months. One-half of each form should be proved at the Torpedo Station and the other half at the proving ground.
“I would take eighty rounds of the Winchesters and eighty of the Mannlichers and subject them for two weeks to the freezing temperature, then for two weeks to a temperature of about 140° F., and then draw twenty of each, and this should be continued until the last forty drawn out have been exposed for eight weeks to freezing and eight weeks to the high temperature. The firing trials with these should be made as with preceding ones.
“The remaining shell should be stored in the regular magazine, to be used in any test case which may arise or in any manner suggested by the results obtained in the tests described above.
“In the meantime tests could be made with the hand-cut S. P. for the capacity of the powder to resist crumbling and dusting during transportation, and the tendency of the fixed ammunition to explode cn masse by the impact of projectiles or by the explosion of a single cartridge in the midst of a box filled with them. The first can be effected by taking a pound or a kilogram of carefully sifted powder, placing in a copper vessel which it only partly fills, and attaching it to a shaft so that it will be continually and violently shaken, and allowing this to go on every working day for a week. The powder can then be sifted, using the same mesh as before, the weight of the dust found and the percentage of dusting for the given circumstances determined.
“In the trials for tendency to explode en masse fifty or forty- five caliber ammunition can be used, and the weights of charges need not be very precise, but the ammunition should be packed in, as nearly as possible, the same way as would obtain in service practice.
“We have seen that the development of smokeless powder has been rendered necessary by the improvement in the gun. It now appears that in consequence of the possession of the powder we must further improve the gun, for we cannot in our present guns utilize all the energy now available. Experiments looking to this have been going on in France, where in a Canet 10-cm. gun of 80 calibers, with a charge of 12.35 pounds of powder and a projectile weighing 28.66 pounds, there was obtained the extraordinary muzzle velocity of 3366 feet per second, while the maximum pressure was 18.91 tons per square inch. Longridge, an English authority, deprecates the lengthening of the gun, as it becomes too unwieldy, and he advocates utilizing the energy by strengthening the gun so it will endure greater pressures and then using larger charges. He points out that if this Canet gun were reduced to 45 calibers and strengthened we could obtain from it the same enormous muzzle velocity by increasing the charge to 13½ pounds, though the pressure would rise to 25 tons per square inch.
“What the result will be where authorities of standing disagree is impossible to foresee, but the fact is demonstrated that the powder is now more highly developed than the gun, and that while seeking for smokelessness, we have secured a propellent which is capable of producing much higher velocities than gunpowder, with all the additional advantages of flat trajectory, increased danger area, greater accuracy and greater range, which follow as consequences.”
Messrs. William Macnab and E. Ristori have carried out a long series of experiments with explosive compounds for the purpose of studying chemical reactions at high temperatures and pressures, and of elucidating certain thermal constants relating chiefly to the specific heat of gases under such conditions, and a portion of their results is published in the Proc. Roy. Soc., 56, 8-19; 1894, under the title of “Researches on Modern Explosives.”
For these experiments they have principally used nitro-gly- cerin, nitro-cellulosc, and several combinations of these two bodies which are used for smokeless gunpowders, for the reason that such modern explosives offer the advantage of not only presenting comparatively simple chemical reactions, owing to the absence of solid residue, but also of enabling considerable variations to be made in their composition so as to vary the proportions of the elements reacting.
In this preliminary communication they propose chiefly to indicate the results obtained in the measurement of the heat evolved by explosion and of the quantity and composition of the gases produced by this metamorphosis.
They have also made considerable progress towards the determination of the actual temperature of explosion, and have succeeded in recording these high temperatures by photographic means, but these results are to be made the subject of another communication at an early date.
The great secret of all these modern explosives seems to be that by suitable means they are made into a solid substance, thus avoiding any porosity, and it appears probable that by doing so even the most powerful explosive can be mastered, so that, burning regularly from the surface, the rate of combusion can be controlled so as to avoid detonation.
This constitutes the most striking feature of the modern smokeless gunpowders, especially of those containing nitro-glycerin. If certain sized cubes, strips or cords of such powders are fired in a certain gun and the length of this gun does not allow of sufficient time during the travel of the shot for the explosive to be entirely consumed, the unburnt residue of the charge will be found to be of the same shape, whether cubes, strips or cords, only reduced in size; thus proving the most perfect surface combustion of these explosives.
It is thus possible to determine accurately what quantity of explosive, and what surface of combustion for the same, will be required, in order to obtain certain results in a certain gun, thus avoiding waste of powder.
The insensitiveness of modern smokeless powder was illustrated on the occasion of a disastrous fire which occurred in May, 1890, at the factory of Avigliana, Italy, where large quantities of ballistite were manufactured. In one building twelve tons of this explosive were collected and various operations of manufacture were performed. By accident some of it took fire, and the whole quantity was burnt in a few seconds. Though this powder was made of nitro-glycerin and nitro-cellulose, and though the amount was so large that had it been black powder it would have caused destruction for many, miles around, still there was no explosion of any kind; none of the machinery was in any way damaged, and the wood was barely charred.
The explosives used in these experiments can be divided into three classes:
1. Those consisting of nitro-lignin or nitro-cellulose (not gelatinized) mixed or impregnated with a suitable nitrate, and mixed with coloring matters and some other substances for the purpose of retarding the rate of combustion.
2. Those consisting of purified nitro-lignin or nitro-cellulose gelatinized by a suitable process, and with or without the addition of nitro-benzene or other suitable nitrates.
3. Those consisting of nitro-cellulose combined with nitroglycerin, with the addition of aniline, camphor, vaseline, or other kindred substances.
The experiments were carried out in two closed vessels of different dimensions and construction—a large one capable of standing high pressures and a small one for calorimetric work.
The large one consists of a steel cylinder of great thickness, closed at both ends by conical screw-plugs. One plug is provided with a crusher-gauge of the well known pattern, by which the compression of a small cylinder of copper serves to measure the pressure developed. The other plug is provided with an insulated conical core, by means of which an electric current can be passed for the purpose of firing the charge. A small hole on the side of the cylinder, bushed with iridium-platinum and closed by a coned screw-plug, serves to control the escape of the gases produced by the explosion. The capacity of the chamber was carefully measured and was found to be 247.6 cc.
The small vessel is of the same pattern as used by Berthelot, and was made by Golaz, of Paris. It has given great satisfaction and is in excellent order, although it has been used for more than two hundred explosions. This bomb, which is made of mild steel and is cylindrical in shape, consists essentially of three parts—a bowl; a conical lid, which is accurately ground into the bowl; and a tightening cap, which screws on to the bowl over the lid. There is a small hole in the lid provided with a delivery tube, which can be opened and closed by means of a finely threaded conical plug. There is also an insulated platinum cone inserted from underneath in the lid, which admits of the charge in the bomb being fired by a platinum wire heated to redness by electricity. From the lid depend platinum supports which carry a platinum capsule, in which the explosive is placed and suspended in the middle of the chamber. The capacity of this bomb is 488 cc., and the total weight, including a small stand, when ready for immersion in the calorimeter, is 5633.28 grams.
The calorimeter is made of thin sheet brass, and a helicoidal stirrer of the same metal (Berthelot’s pattern), driven by a small electromotor during the experiment, serves to thoroughly mix the water. The calorimeter stood in the center of an annular water-jacket covered with felt. The quantity of water used in the calorimeter each time was 2500 grams, and the equivalent in water of the bomb, stirrer and calorimeter, due allowance having been made for the different specific heats of the different metals, is 623.4 grams.
The different thermometers employed were specially made by Casella, capable of being read to 0.005 of a degree centigrade, and the weights of their stems, bulbs and mercury were known.
Various experiments were made in the large vessel, especially for the purpose of determining the pressure of the gases under different densities of charge. These trials were carried out in a field, the bomb being lowered into a hole in the ground before firing. Various difficulties were encountered, and in one experiment considerable damage was done by the heated gases effecting their escape at the moment of explosion and “washing away” part of the thread of one of the screw-plugs.
With the density of loading of ∆ = 0.1, i. e., with a charge of 24.76 grams, the average of the pressures measured was 6.3 tons per square inch; with density ∆ = 0.2 the pressure rose to 15 tons, and with ∆ = 0.3 the pressure increased to 25 tons. These results are very similar to those published by Sir A. Noble, F.R.S.
With the small bomb were ascertained the amount of heat generated by the explosion, the volume and composition of the permanent gases resulting, and the quantity of aqueous vapor produced. As most of the explosives contained no mineral matter beyond a trifling percentage of “ash,” it has been possible to analyze them in this way, the products of explosion when calculated from the analysis and volume of permanent gas and aqueous vapor agreeing closely with the weight of matter in the bomb before firing. A few of the explosives left a carbonaceous or mineral residue, but these will be specially noticed further on in connection with the table of the results.
The heat evolved was measured by placing the bomb containing the charge of explosive in the calorimeter containing 2500 grams of water, and it was arranged that the temperature of the air, the water-jacket, and the calorimeter closely approximated each other. The stirrer was set in motion, and the thermometer in the calorimeter was read with a kathetometer. Observations of the temperatures were made every minute for the five minutes preceding the firing of the charge, and continued at intervals of a minute until the maximum was reached and for five minutes longer. The correction for loss of heat due to radiation of heat during the experiments amounted in general to about 0.01 of a degree. The increase in temperature varied from about 1° to 2½° C., according to the charge and explosive used.
The gas generated by the explosion was passed through weighed drying tubes connected with the valve on the lid of the vessel, and then collected and measured in a calibrated glass cylinder over mercury. The reading of the barometer and thermometer was noted, and the volume reduced to 0° C. and 760 mm.
The water was determined by immersing the bomb in a vessel containing boiling water. A three-way glass stop-cock intervened between the valve of the bomb and the drying tubes, and the other end of the drying apparatus was connected with a water vacuum pump.
The other branch of the three-way tap was connected with a separate drying apparatus. When the water surrounding the bulb was boiling, by starting the vacuum pump the steam and water were drawn into the absorbing apparatus; after a good vacuum had been made in the bomb the three-way tap was turned so that dry air rushed in, then connection was made with the drying apparatus, the bomb again exhausted, and so on, alternately, until (as experience showed) all the water had been removed from the bomb and collected in the drying tubes, which were then weighed. The weights of water thus obtained were calculated for comparison into volumes of H20 gas at 0° C. and 760 mm.
The analyses of gas were carried out in duplicate in Dittmar’s apparatus as improved by Lennox.
In most of the experiments the bomb, previous to firing, was exhausted and the amount of residual pressure, varying from 24 to 40 mm., noted on closing it. The amount of air corresponding to these pressures left in the bomb has the effect of increasing the heat generated by a small quantity amounting to five to seven calories. This quantity being within the limits of error of the calorimetric observation, no correction was made for the same, but the quantity of residual air was taken into account when comparing the weights of the products found with the weight of the explosive used. Thus in Tables I and II the volumes of gas of the given composition and of aqueous vapor were obtained from the given weight of explosive increased by the weight of the air corresponding to the vacuum indicated. When firing in an exhausted bomb it was found necessary to have the explosive surrounding the firing wire in comparatively small pieces, in order to ensure ignition of the whole charge.
Table I.—Indicating the Quantity of Heat, also the Volume and Analysis of the Gas developed per Gram with Different Sporting and Military Smokeless Powders now in Use.
Name of explosive. | Calories per gram. | Permanent gases. | Aqueous vapor. | Total volume of gas calculated at 0° and 760 mm. | Per cent, composition of permanent gases. | Coefficient of potential energy. | ||||
CO2 | CO. | CH4. | H. | N. | ||||||
|
| Cc. per gram. | Cc. per gram. | Cc. per gram. |
|
|
|
|
|
|
EC powder, English | 800 | 420 | 154 | 574 | 22.9 | 40.6 | 0.5 | 15.5 | 20.5 | 459 |
SS sporting powder, English | 799 | 584 | 150 | 734 | 18.2 | 454 | 0.7 | 30.0 | 15.7 | 586 |
Troisdorf, German | 943 | 700 | 195 | 895 | 18.7 | 479 | 0.8 | 17.4 | 15.2 | 844 |
Rifleite, English | 864 | 766 | 159 | 925 | 14.2 | 50.1 | 0.3 | 30.5 | 14.9 | 799 |
BN, French | 833 | 738 | 168 | 906 | 13.2 | 53.1 | 0 7 | 14.8 | 13.6 | 755 |
Cordite, English manufacture. | 1253 | 647 | 235 | 882 | 24.9 | 40.3 | 0.7 | 14.8 | 1.33 | 1105 |
Ballistite, German manufacture | 1391 | 591 | 331 | 833 | 33.1 | 35.4 | 0.5 | 10.1 | 30.9 | 1067 |
Ballistite, Italian and Spanish manufacture | 13.7 | 581 | 245 | 826 | 35.9 | 33.6 | 0.3 | 9.0 | 222 | 1088 |
Table I gives the principal results obtained with the several gunpowders above mentioned, Tables II and III give the results obtained with samples of ballistite made with different proportions of the component parts, Table IV indicates the effect of firing different weights of the same explosive in a closed vessel from which the air has not been exhausted, and Table V gives the original elementary composition of several explosives compared with the products of combustion, both being represented as weights.
With the exception of the results given in Table IV, all the others were obtained from the firing of 4 grams of the explosive.
In Tables I and II we have expressed the results of firing some powders now in use, as well as certain specially prepared powders, so as to show the quantity of heat and the volumes and analyses of the gases produced, and have in the column headed “Coefficient of potential energy,” given figures which serve as a measure of comparison of the power of the several explosives. These figures are the products of the number of calories by the volumes of gas, the last three figures being suppressed in order to simplify the results.
In the case of EC and SS a certain amount of mineral residue was left, but this was not determined.
Table II.—Indicating the Quantity of Heat, also the Volume and Analysis ok the Gas developed per Gram with Nitro-glycerin, Nitro-ckllulosk, and with Several Different ComBinations of these Two Explosives made at Ardeer Factory.
Composition of explosive. | Calories per gram. | Permanent gases. | Aqueous vapor. | Total volume of gas calculated at 0° and 760 mm. | Per cent, composition of permanent gases. | Coefficient of potential energy. | ||||||
CO2. | CO. | CH4. | O. | H. | N. | |||||||
|
|
| Cc. per gram. | Cc. per gram. | Cc. per gram. |
|
|
|
|
|
|
|
A. | Nitro-glycerin. | 1652 | 464 | 257 | 741 | 63.0 | . . | . . | 4.0 | . . | 33.0 | 1224 |
B. | Nitro-cellulose (nitrogen = 13.30 per cent.) | 1061 | 673 | 203 | 876 | 22.3 | 45.4 | 0.5 | . . | 14.9 | 16.9 | 929 |
C. | 50 per cent, (nitrocellulose (N=12.24 per cent.). | 1349 | 568 | 249 | 817 | 36.5 | 32.5 | 0.2 | . . | 8.4 | 22.4 | 1102 |
D. | 50 per cent, (nitrocellulose (N = 13.3 per cent.). | 1410 | 550 | 247 | 797 | 41.8 | 27.5 | . . | . . | 6.0 | 24.7 | 1124 |
E. | 80 per cent, nitrocellulose (N=12.24 per cent.) | 1062 | 675 | 226 | 901 | 21.7 | 45-4 | 0.1 | . . | 15.7 | 17.1 | 957 |
F. | 80 per cent, nitrocellulose (N=13.30 per cent.). | 1159 | 637 | 227 | 864 | 26.6 | 40.8 | 0.1 | . . | 12.0 | 20.5 | 1001 |
G. | 35 per cent, nitrocellulose (N=13.30 per cent.). | 1380 | 627 | 236 | 863 | 26.7 | 39 8 | 0.5 | . . | 12.8 | 20.2 | 1105 |
Table III.—Showing thk Heat developed by Explosives containing Nitro-glycerin and Nitro-cellulose in Different Proportions.
Composition of Explosives. | Calories per gram. | ||
Nitro-cellulose (N = 13.3 per cent.). | Nitro-glycerin. | ||
100 per cent, (dry pulp). | 0 | 1061 | |
100 ““(gelatinized). | 0 | 922 | |
90 " “ |
| 10 per cent. | 1044 |
80 “ “ |
| 20 “ “ | 1159 |
70 “ “ |
| 30 “ “ | 1267 |
60 “ “ |
| 40 “ “ | 1347 |
50 “ “ |
| 50 “ “ | 1410 |
40 “ “ |
| 60 ““ | 1467 |
O “ " |
| 100 ““ | 1652 |
Nitro-cellulose (N = 12.24 percent.). | Nitro-glycerin. |
| |
80 per cent. |
| 20 per cent. | 1062 |
60 “ “ |
| 40 “ “ | 1288 |
50 “ " |
| 50 “ “ | 1349 |
40 “ “ |
| 60 “ “ | 1405 |
Nitro-cellulose (N = 13.3 percent.) | Vaseline. | Nitro-glycerin. |
|
55 per cent. | 5 per cent. | 40 per cent. | 1134 |
35 “ “ | 5 “ “ | 60 “ “ | 1280 |
Troisdorf leaves a slight, and Rifieite and BN a considerable, carbonaceous residue, part of it adhering so tenaciously to the bomb that an exact determination was not made.
In the other experiments recorded in Tables I and II the degree of accuracy of the results may be gauged by the fact that the average weight of the products of explosion, calculated from the results found, amounts to 99.7 per cent, of the weight of the explosive fired, the extreme limits being 100.5 and 98.9 per cent.
In Table II the comparison of the pairs of results from explosives made with lower and more highly nitrated nitro-cellulose shows that the use of the highly nitrated cellulose increases the quantity of heat developed and diminishes the volume of gas. The composition of the permanent gases is also altered, as might be expected, there being an increase in carbon dioxide and decrease in carbon monoxide and hydrogen.
The similarity in the volumes of gas produced and the composition of the permanent gases in the case of experiments F and G is worthy of note when the great difference in the original component ingredients of the explosives is borne in mind.
Table III shows clearly the increase of heat due to increased percentage of nitro-glycerin, as well as the difference of heat evolved from explosives containing nitro-cellulose of different degrees of nitration.
The diminution in quantity of heat (about 200 calories) which the replacement of 5 per cent, of nitro-cellulose by vaseline makes is also very striking.
Table IV shows the part played by the oxygen of the air in the bomb; when a smaller proportion of explosive In comparison with the air is present the combustion is more complete, and the heat evolved is greater, and the composition of the gases is correspondingly modified.
Table IV.—Showing the Heat developed and the Analysis op the Permanent Gas produced in a Closed Vessel from which the Air HAS NOT BEEN EXHAUSTED—THE EXPLOSIVE BEING IN EVERY CASE Ballistite of Italian Manufacture.
Charge. | Calories per gram. | Analysis of the permanent gas. | |||
CO2. | CO. | H. | N. | ||
2 grams | 1587 | 37.0 | 17.6 | 3.2 | 42.2 |
3 “ | 1485 | 36.4 | 22.0 | 4.6 | 37.0 |
4 " | 1446 | 36.2 | 24.6 | 6.1 | 33.1 |
5 “ | 1415 | 36.2 | 26.0 | 7.2 | 30.6 |
6 “ | 1380 | 36.3 | 27.0 | 7.9 | 28.6 |
Traces of CH, were found, but in this series of experiments the quantity of this gas was not determined.
Table V, the elementary composition of some of the explosives, along with the percentage composition of the products of explosion by weight, is given.
Table V.—Showing the Original Composition and Metamorphosis of Nitro-cellulose, Nitro-glyckrin, and of Several Gunpowders made by Combinations of these Two Explosives.
Nature and description of explosives. | Per cent composition by weight. | Per cent. products of combustion by weight, | ||||||||||
Carbon, C. | Oxygen, O. | Hydrogen, H. | Nitrogen, N. | Carbonic acid, CO2. | Carbonic oxide, CO. | Marsh gas, CH4. | Oxygen, | Hydrogen, H. | Nitrogen, N. | Water, H2O. | ||
A. | Nitro-glycerin. | 15.7 | 63.0 | 2.3 | 18.8 | 57.6 | . . | . . | 2.7 | . . | 18.8 | 20.7 |
B. | Nitro-cellulose (nitrogen=13.3). | 24.58 | 57.68 | 2.73 | 13.6 | 29.27 | 38.5. | 0.34 | . . | 0.86 | 13.6 | 16.30 |
C. | 50 per cent, nitrocellulose (N=12.24 per cent.). | 21.15 | 60.67 | 2.67 | 15.58 | 41.0 | 23.1 | 0.08 | . . | 0.4 | 15.58 | 20.01 |
D. | 50 per cent, nitrocellulose (N=13.30 per cent.). | 20.47 | 61.23 | 2.49 | 16.35 | 45.3 | 19.0 | . . | . . | 0.3 | 16.35 | 19.90 |
E. | 80 per cent, nitrocellulose (N=12.24 per cent.). | 24.37 | 58.98 | 2.98 | 14.0 | 28.9 | 38.4 | 0.05 | . . | 1.0 | 14.0 | 18.2 |
F. | 80 per cent, nitrocellulose (N=13.30 per cent.). | 23.11 | 58.98 | 2.71 | 15.84 | 33.4 | 32.6 | 0.04 | . . | 0.7 | 15.84 | 182 |
G. | 35 per cent, nitrocellulose (N=13.30 per cent.) | 22.2 | 59.0 | 3.88 | 15.46 | 33.0 | 31.3 | 0.2 | . . | 0.7 | 15.46 | 19.0 |
H. | Cordite, English manufacture. | 22.91 | 57.72 | 2.95 | 15.19 | 31.76 | 32.68 | 0.32 | . . | 0.86 | 15.19 | 18.08 |
K. | Ballistic, Italian and Spanish manufacture. | 21.47 | 60.83 | 2.68 | 15.80 | 41.11 | .3.76 | 0.12 | . . | 0.47 | 15.8 | 19.69 |
The composition of the samples has been calculated from the “bomb” analyses; as an example, one of the explosives and its decomposition may be represented approximately by the following equation.
They have assumed the nitro-cellulose to consist of a mixture of di- and tri-nitro-cellulose in proportion corresponding to the nitrogen as found by analysis. NOTES ON THE LITERATURE OF EXPLOSIVES.
The equation for experiment C may be taken as follows:
50 per cent. nitro-glycerin. 50 per cent, nitro-cellulose (N=12.3 per cent.).
6 [C3H5(NO3)3] + 2 [C6H7 (NO3)3O2] + 3 [C6H8(NO3)2O8] =
25CO2 + 23CO + 8H + 30N + 30H2O.
The composition of this explosive, calculated from the foregoing formula and found by analysis, is as follows:
| FORMULA. | ANALYSIS. |
C.................................................. | 21.2 | 21.15 |
O............................................. | 60.8 | 60.67 |
H............................................. | 2.5 | 2.67 |
N............................................. | 15.5 | 15.58 |
| 100.0 | 100.07 |
These are some of the principal features noticeable in a preliminary survey of these experiments. They are continuing their investigations on the lines indicated in the paper, and are especially endeavoring to measure the actual temperature of explosion under varying conditions, and it is hoped that the result obtained will throw some light on the chemical and physical properties of many gases at high temperatures and under considerable pressures, and, at the same time, be useful in the practical application of explosives.
The “Researches on Explosives,” on which Capt. A. Noble and Sir F. Abel have been engaged for very many years, have had their scope so altered and extended by the rapid advances which have been made in the science of explosives that they have been unable to lay before the Society the results of the many hundreds of experiments carried out under varied conditions. They have been desirous of clearing up some difficulties which have presented themselves with certain modern explosives when dealing with high densities and pressures, but the necessary investigations have occupied so much time that Capt. Noble has issued a preliminary note in the Proceedings Royal Society, 56, 205-221; 1894, trusting before long to be able to submit a more complete memoir.
A portion of their reasearches includes investigations into the transformation and ballistic properties of powders varying greatly in composition, but of which potassium nitrate is the chief constituent. In this preliminary note it is proposed to refer to powders of this description chiefly for purposes of comparison, and to devote attention principally to gun-cotton and to those modern explosives of which gun-cotton forms a principal ingredient.
In determining the transformation experienced during explosion, the same arrangements for firing the explosive and collecting the gases were followed as are described in their earlier researches,* and the gases themselves were, after being sealed, analyzed either under the personal superintendence of Sir F. Abel or of Prof. Dewar.
The heat developed by explosion and the quantity of permanent gases generated were also determined, as described in their researches, but the amount of water formed plays so important a part in the transformation that special means were adopted in order to obtain this product with exactness.
The arrangement) employed was as follows: After the explosion the gases formed were allowed to escape through two U tubes filled with pumice stone and concentrated sulphuric acid; when the gases had all escaped the explosion cylinder was opened and the water deposited at the bottom of the cylinder was collected in a sponge, placed in a closed glass vessel and weighed. The cylinder was then nearly closed and heated, and a measured quantity of air was, by means of an aspirator, drawn slowly through the U tubes till the cylinder was perfectly dry. This was easily ascertained by observing when moisture was no longer deposited on a cooled glass tube through which the air passed.
The U tubes were then carefully weighed, the amount of moisture absorbed determined and added to the quantity of water directly collected. The aqueous vapor in the air employed for drying was, for each experiment, determined and deducted from the gross amount.
Numerous experiments were made to ascertain the relation of the tension of the various explosives employed, to the gravimetric density of the charge when fired in a close vessel, but this subject is too large to be treated of in a preliminary note, and besides approximate values have already been published* for several of the explosives with which they have experimented.
With certain explosives the possibility or probability of detonation was very carefully investigated. In some cases the explosive was merely placed in the explosion vessel in close proximity to a charge of mercuric fulminate, by which it was fired, but the most satisfactory method was to place the charge in a small shell packed as tightly as possible, the shell then being placed in a large explosion vessel and fired by means of mercuric fulminate. The tension in the small shell at the moment of fracture and the tension in the large explosion vessel were in each experiment carefully measured.
Capt. Noble does not consider the presence of a high pressure with any explosive as necessarily denoting detonation. Both cordite and gun-cotton have developed enormous pressures, close upon 100 tons per square inch (about 15,000 atmospheres), but he has not succeeded in detonating the former explosive, while gun-cotton can be detonated with the utmost ease. It is obvious that if we suppose a small charge fired in a vessel impervious to heat, the rapidity or slowness of combustion will make no difference in the developed pressure, and that pressure will be the highest of which the explosive is capable, regard being of course had to the density of the charge. A small charge is supposed, because if a large charge were in question and explosion took place with extreme rapidity, the nascent gases may give rise to such whirlwinds of pressure that any means we may have of registering the tension will show pressures very much higher than would be registered were the gases, at the same temperature, in a state of quiescence. Innumerable proofs have been had of this action, but it is evident that in a very small charge the nascent gases will have much less energy than in the case of a large charge occupying a considerable space.
The great increase in the magnitude of the charges fired from modern guns has rendered the question of erosion one of great importance. Few, who have not had actual experience, have any idea how rapidly with very large charges the surface of the bore is removed. Great attention has therefore been paid to this point, both in regard to the erosive power of different explosives and in regard to the capacity of different materials (chiefly different natures of steel) to resist the erosive action. The method adopted consisted in allowing large charges to escape through a small vent. The amount of the metal removed by the passage of the products of explosion, which amount was determined by calibration, was taken as a measure of the erosive power of the explosive.
Experiments were also made to determine the rate at which the products of explosion part with their heat to the surrounding envelope, the products of explosion being altogether confined.
Turning now to ballistic results, the energies which the new explosives are capable of developing, and the high pressures at which the resulting gases are discharged from the muzzle of the gun, render length of bore of increased importance. With the object of ascertaining with more precision the advantages to be gained by length, the firm to which Captain Noble belongs has experimented with a 6-inch gun of 100 calibers in length. In these experiments the velocity and energy generated has not only been measured at the muzzle, but the velocity and the pressure producing this velocity have been obtained for every point of the bore, consequently the loss of velocity and energy due to any particular shortening of the bore can be at once deduced. These results have been obtained by measuring the velocities every round at sixteen points in the bore and at the muzzle. These data enable a velocity curve to be laid down, while from this curve the corresponding pressure curve can be calculated. The maximum chamber pressure obtained by these means is corroborated by simultaneous observations taken with crusher gauges, and the internal ballistics of various explosives have thus been completely determined.
Commencing with gun-cotton, with which a very large number of analyses were made, with the view of determining whether there was any material difference in the decomposition dependent upon the pressure under which it was exploded, two descriptions were employed: one in the form of hank or strand, and the other in the form of compressed pellets. Both natures were approximately of the same composition, of Waltham Abbey manufacture, containing in a dried sample about 4.4 per cent, of soluble cotton and 95.6 per cent, of insoluble. As used, it contained about 2.25 per cent, of moisture.
The following were the results of the analyses of the permanent gases. They are placed in five series, viz.: First, analyses showing the decomposition of the strand or hank gun-cotton; second, analyses showing the decomposition of pellet gun-cotton; third and fourth, examples of the decomposition of strand and pellet gun-cotton when exploded by means of mercuric fulminate; and fifth, a series showing the decomposition experienced by pellet gun-cotton saturated with from 25 to 30 per cent, of water, and detonated by means of a primer of dry gun-cotton and mercuric fulminate.
In Tables I and II the marked manner in which the carbon dioxide increases with the pressure, and which has been heretofore noted for gunpowder, is again exhibited. It will be observed that in Table I the volumes of carbon dioxide and carbon monoxide are nearly exactly reversed; again, considering that the composition of the pellet and strand gun-cotton is practically the same, the distinct difference between the proportions of these products in the two series is sufficiently remarkable. It not improbably is connected with the rapidity of combustion of the two samples. Another striking peculiarity is the manner in which C02 is increased (as exhibited in Table V) when saturated pellet cotton is detonated.
I.—Results in Volumes of the Analyses ok the Permanent Gases GENERATED UY THE EXPLOSION OF STRAND GUN-COTTON, ARRANGED ACCORDING TO ASCENDING PRESSURES.
[TABLE]
II.—SIMILAR ANALYSES OF PELLET GUN-COTTON.
[TABLE]
III.—RESULTS OF THE ANALYSES OF STRAND GUN-COTTON WHEN FIRED IN A CLOSE VESSEL BY DETONATION.
[TABLE]
IV.—SIMILAR RESULTS FOR PELLET GUN-COTTON.
[TABLE]
V.—RESULTS OF ANALYES OF SATURATED PELLET GUN-COTTON FIRED IN A CLOSE VESSEL BY DETONATION.
Such are the average analyses of the permanent gases generated by the decomposition of gun-cotton under the various conditions described, and it will be evident from these analyses that the volumes of the permanent gases may be expected to differ to some very appreciable extent, depending both upon the density under which it is exploded and also upon the mode of explosion. He has found it most convenient to explode the charges, the permanent gases from which were to be measured, under a pressure of about 10 tons per square inch (1524 atmospheres), and, under these circumstances, the average of several very accordant determinations gave, at 0° C. and 760 mm. of mercury, 689 cc. per gram of strand gun-cotton and 725 cc. per gram of pellet gun-cotton.
At the temperature of explosion the whole of the water formed is in the gaseous state. It is therefore necessary, in order to obtain the total gaseous volume, to add to the above volumes of permanent gases the equivalent volume of aqueous vapor at the temperature and pressure stated. Now the quantity of water formed by the explosion of 129.6 grams of gun-cotton was found to be 16.985 grams; hence 1 gram of gun-cotton generated 0.1311 gram of water, equivalent to 162.6 cc. of aqueous vapor, and the total volume of gaseous matter at the temperature and pressure stated is for strand gun-cotton 852.2 cc. per gram, for pellet 887.6 cc.
The heat measured reached, with strand gun-cotton, 1068 gram-units water fluid, or 988 gram-units water gaseous, while with pellet gun-cotton these figures were 1037 or 957 gram-units respectively. Pellet gun-cotton made at Stowmarket generated 738 cc. of permanent gas and 994 units of heat per gram, while dinitro-cellulose containing 12.8 per cent, of nitrogen generated 748 cc. of gas and 977 units of heat, the water in both cases being fluid.
Gun-cotton, both pellet and strand, were detonated by means of mercuric fulminate with ease and certainty. The effect of employing this means of ignition in a close vessel is very striking, and the indications of intense heat are much more apparent than when the charge is fired in the ordinary way. This effect is probably partly due to an actual higher temperature, caused by the greater rapidity of combustion. This extreme heat is clearly indicated by the surfaces of the internal crusher gauges becoming covered with innumerable small cracks and by thin laminae occasionally flaking off exposed surfaces; but perhaps the most striking proof of the violence of this detonation is shown by its action on a cast-iron shell fired as described; where no detonation takes place the shell is broken into fragments of various sizes, such as are familiar to all acquainted with the bursting of shell; but when detonation, with gun-cotton for example, takes place the whole shell is reduced to very minute fragments, and, what is more remarkable, two-thirds of the total weight are generally in the form of small peas and of the finest dust.
The ease with which gun-cotton can be detonated renders it unsuitable for use as a propulsive agent unless this property be in some way neutralized. He has, therefore, made but few experiments in this direction, and will not further allude to them in this note, as more suitable explosives, explosives also of which gun-cotton is a principal component, have been elaborated, and these not only possess to the full the high ballistic properties of gun-cotton, but are more or less free from the tendency to detonate, which, however useful it may be in other directions, is a fatal objection to the employment of gun-cotton for propelling purposes.
Turning now to cordite; cordite consists, as is well known, of nitro-glycerin and gun-cotton as its main ingredients. As now made it contains 37 per cent, of gun-cotton (trinitro-cellulose with a small proportion of soluble gun-cotton), 58 per cent, of nitro-glycerin, and 5 per cent, of vaselin. On account of the importance of this explosive, he has made numerous experiments, both with large and small charges, to determine the relation of the tension to the density of the charge. Up to densities of 0.55 the relation may be considered to be very approximately determined; above that density, although many determinations have been made, these determinations have shown such wide variations that they cannot, until certain discrepancies are explained, be assumed as at all accurate.
The average results of some of the analyses of the permanent gases are given below. The first four analyses were made from experiments with the earlier samples of cordite when tannin formed an ingredient of cordite. They are not, therefore, strictly comparable with the later analyses. There appears also to be a difference in the transformation, slight but decided, which the same cordite experiences, dependent upon the diameter of the cord, and this difference is shown at once in the analyses, in the volume of permanent gases, in the heat developed, and, I think, in the amount of aqueous vapor formed.
The following are some of the analyses:
Table VI.
[TABLE]
In the whole of these analyses the water formed by the explosion smelt strongly of ammonia.
The quantity of permanent gases measured, under the same conditions as in the case of gun-cotton, was found to be, for the earlier cordite, 655 vols.; for the present service cordite, 0.255 in. in diameter, 692 vols., and for that 0.048 in. in diameter, 698 vols. In the two latter samples the aqueous vapor was determined, and was found to amount to 20.257 grams for the 0.255-in. cordite and to 20.126 grams for the 0.048-in. cordite; or, stating the result per gram, these figures are respectively equivalent to 0.1563 gram or 194 cc. aqueous vapor, and to 0.1553 gram or 192.5 cc. per gram of cordite. Hence the total gaseous products generated by the explosion of cordite amount per gram to 886 cc. for the 0.255-in. cordite and to 890.5 cc. for the 0.048-in. cordite, the volumes being of course taken at 0° C. and 760 mm. atmospheric pressure.
The heat generated was found to be: for the earlier cordite, 1214 gram-units water fluid; for the service 0.255-in. cordite, 1284 gram-units water fluid or 1189 units water gaseous; for the service 0.048-in. cordite, 1272 units water fluid or 1178 units water gaseous.
From his very numerous experiments on erosion he arrives at the conclusion that the principal factors determining its amount are: (1) the actual temperature of the products of combustion, (2) the motion of these products. But little erosive effect is produced, even by the most erosive powders, in close vessels, or in those portions of the chambers of guns where the motion of the gas is feeble or nil; but the case is widely different where there is rapid motion of the gases at high densities. It is not difficult absolutely to retain without leakage the products of explosions at very high pressures, but if there be any appreciable escape before the gases are cooled they instantly cut a way for themselves with astonishing rapidity, totally destroying the surfaces over or through which they pass. Among all the explosives with which I have experimented I have found that where the heat developed is low the erosive effect is also low.
The most erosive of ordinary powders is the brown prismatic powder, which, on account of other properties, is used for the battering charges of heavy guns. The erosive effect of cordite, if considered in relation to the energy generated by the two explosives, is very slightly greater than that of brown prismatic, but very much higher effects can, if it be so desired, be obtained with cordite, and, if the highest energy be demanded, the erosion will be proportionately greater. There is, however, one curious and satisfactory peculiarity connected with erosion by cordite. Erosion produced by the ordinary gunpowder has the most singular effect on the metal of the gun, eating out large holes and forming long rough grooves, resembling a ploughed field in miniature, and these grooves have, moreover, the unpleasant habit of being very apt to develop cracks; but with cordite the erosion is of a very different character. The eddy holes and long grooves are absent, and the erosion appears to consist in a simple washing away of the surface of the steel barrel.
Cordite does not detonate; at least, although he has made far more experiments on detonation with this explosive than with any other, he has never succeeded in detonating it. With an explosive like cordite, capable of developing enormous pressures, it is of course easy, if the cordite be finely comminuted, to develop very high tensions, but a high pressure does not necessarily imply detonation.
The rapidity with which cordite gases lose their temperature, and consequently their pressure, by communication of their heat to their surrounding envelope is very striking. Exploding a charge of about if lbs. of cordite in a close vessel at a tension of a little over 6 tons on the square inch, or say 1000 atmospheres, he has found that the pressure of 6 tons per square inch was again reached in 0.07 sec. after explosion, of 5 tons in 0.171 sec., of 4 tons in 0.731 sec., of 3 tons in 1.764 secs., of 2 tons in 3.523 secs., and of 1 ton in 7.08 secs. The loss of pressure after 1 ton per square inch was reached was of course slow, but the figures given are closely approximated to in two subsequent experiments. With ordinary gunpowder the reduction of pressure was very much slower, as was to be expected, on account of the charge being much larger; on account, also, of the temperature of explosion being much lower. These experiments are now being continued with larger charges and higher pressures.
It only remains to give particulars as to ballistics, that is as to the velocities and energies realisable by cordite in the bore of a gun, but these will be most conveniently given with similar details regarding other explosives.
The ballistite used has, like cordite, been changed in composition since the commencement of the experiments. The sample used for his earlier experiments was nearly exactly composed of 50 per cent, of dinitro-cellulose (collodion cotton) and 50 per cent, of nitro-glycerin. The cubes were coated with graphite, and the nitro-cellulose was wholly soluble in ether-alcohol. The second sample was nominally composed of 60 per cent, of nitrocellulose and 40 per cent, of nitro-glycerin. The proximate analysis gave—
Nitro-glycerin..................................................... 41.62
Nitro-cellulose ................................................... 59.05
and, as before, the whole of the nitro-cellulose was soluble in ether-alcohol.
The earlier sample gave the following permanent gases under pressures of six and twelve tons per square inch respectively:
CO2 ................................................. 37.3.......... 38.49
CO .................................................. 27.8.......... 28.35
H..................................................... 19.1.......... 19.83
N..................................................... 15.8.......... 13.32
CH4............................................................ traces
One gram of this ballistite gives rise to 610 cc. of permanent gases, and to 0.1588 gram of aqueous vapor corresponding to 197 cc. at 0° C. and 760 mm.
Hence the total volume of gas is 807 cc., and the heat generated by the explosion is 1.365 gram-units (water fluid), 1.269 gram- units (water gaseous).
Although he has not made nearly so many experiments on detonation with ballistite as with cordite, those he has made with the earlier samples (50 per cent, gun-cotton and 50 per cent, nitro-glycerin) neither detonated nor showed any tendency to, but a sample of ballistite consisting of 60 per cent, gun-cotton and 40 per cent, nitro-glycerin, in 0.2-in. cubes, detonated with great violence on two occasions, though he is unable, without further experience, to say whether this result was due to the change in the composition of the ballistite or to defective manufacture.
The erosive action of ballistite is, as might perhaps be anticipated from the higher heat developed, greater than with cordite, but the remarks made with respect to the action of cordite apply also to ballistite.
The French B. N. powder consists of nitro-cellulose partially gelatinized and mixed with tannin, with barium and potassium nitrates. When exploded under a pressure of six tons per square inch the permanent gases were found to consist of—
CO2 28.1 vols.
CO 32.4 "
H 21.9 "
N 16.8 "
CH4 0.8 "
These permanent gases occupied at the usual temperature and pressure a volume of 616 cc.; the aqueous vapor formed occupied in addition 206 cc., so that the total gaseous volume was 822 cc. The heat generated was 1003 gram-units (water fluid), or 902 gram-units (water gaseous); the ballistics obtained with this powder are given along with those furnished by other explosives.
The results of the firing trials are exhibited by three plates. Fig. 1 shows the velocities of seven different explosives from the commencement of motion to the muzzle of the gun; the position of the points at which the velocity is determined is shown, and on the lowest and highest curves the observed velocities are marked where it is possible to do so without confusing the diagram. Lines are drawn to indicate the velocities that are obtained with the lengths of 40, 50, 75, and 100 calibers.
Fig. 2 shows the pressures by which the velocities of Fig. 1 were obtained. The areas of these curves represent the energies realized, and the lines intersecting the curves indicate the pressures at which the gases are discharged from the muzzle for lengths of 40, 50, 75, and 100 calibers respectively. The chamber pressures indicated by crusher gauges are also shown in Fig. 2, and it is to be observed that the two modes of determining the maximum pressure are in general in close accordance. It will further be observed that with the slow-burning powders the chronoscopic maximum pressures are somewhat, though not greatly higher than are those indicated by the crusher gauges. This observation is not new.* It was noted in the long series of experiments with black powders carried on by the Committee of Explosives. The result is widely different where an explosive powder or a quickly-burning powder, such as R. L. G., giving rise to wave pressure is employed; the crusher gauge in such cases* gives considerably and frequently very greatly higher pressures, and this peculiarity is illustrated in the curve from R. L. G. in Fig. 2.
The results given in Fig. 1 have to be considered in relation to the facts disclosed in Fig. 2. Thus it will be noted that the velocities and energies realized by 22 lbs. of 0.35-in. cordite and 20 lbs. of 0.3-in. cordite are practically the same, but reference to Fig. 2 shows that with the 0.3-in. cordite this velocity and energy has been obtained at the cost of nearly 30 per cent, higher maximum pressure. A similar remark may be made in regard to the French B. N. powder if compared with the ballistite. Its velocity and energy arc obtained at a high cost of maximum pressure, and it is interesting to note how the velocity curve of B. N., which for the first four feet of motion shows a velocity higher than that of any other explosive, successively crosses other curves, and gives at the muzzle a velocity of 500 f. s. under that of cordite.
The velocities and energies at the principal points indicated in Figs. 1 and 2 are summarized in the annexed table, which shows for each nature of explosive the advantage in velocity and energy to be gained by a corresponding lengthening of the gun.
Fig. 3 offers an interesting illustration of a point elsewhere adverted to. Cordite and ballistite leave no deposit in the bore. Round 1 with R. L. G. was fired with a clean bore. The difference in velocity between round 1 with a clean bore and rounds 2 and 3 with powder deposit in the chase is very clearly marked, and it is shown that in this instance the effect of the foul bore is only distinctly evident when the length exceeds 40 calibers. From 40 calibers onwards the loss of velocity due to a bore encrusted with deposit is very distinctly shown.
Table showing the Velocities and Energies realized in a 6" Gun with the Undermentioned Explosives.
[TABLE]
Under the title, “Inspection of Cotton for Use in the Manufacture of Gun-cotton,” Charles E. Munroe gives in Jour. American Chemical Society, 17, 783-789; 1895, a detailed description of the tests which are applied, with data from the testing of several samples.
The erection of batteries of pneumatic guns along our coast makes the account of the “Pneumatic Torpedo Plant at Fort Winfield Scott,” San Francisco, contributed to the Mining and Scientific Press, San Francisco, December 21, 1895, of interest, especially as it was constructed by Mr. Rix.
The Rix air compressors used for compressing the air are two in number and of the duplex pattern, each of about 400 H. P. capacity. The air is compressed in the first cylinders to 75 lbs. to the square inch, and is thence taken into a cooling tank containing about 1000 running feet of one-inch copper pipes, in which the air is cooled from the temperature of its discharge from initial cylinders, which is about 320 degrees, to the temperature of the water or thereabouts. It is delivered to the intermediate cylinder at about 65 degrees in temperature, and is there compressed in a single-acting ram to about 400 lbs pressure. The air is thence taken again into the intercooling chamber, through about 400 feet of copper pipe, and is cooled again to the temperature of the water, and is delivered to the high-pressure cylinder at the same temperature as to the intermediate cylinder.
In the third cylinder it is compressed to 2000 lbs., the air being delivered at a temperature of about 358 degrees. This is conducted to the third intercooler, where the temperature is reduced to about 65 degrees, and is thence conducted to the storage reservoir.
The engines which drive this compressing plant are of the Meyers cut-off style, and are extremely well balanced and well constructed; in fact, the cards and the results show that these compressors have a mechanical efficiency of about 85%, and throughout the system there is a saving of 36% over the work required to compress the air to 2000 lbs. adiabatically.
The amount of air delivered per hour, at 2000 lbs., is about 460 cubic feet, which is more than ample to keep the machines in operation; in fact, during the test one machine would have been sufficient to have maintained the number of shots.
One feature about this whole compressing plant is the facility with which the air is cooled. Each cylinder has a number of independent circulations, notably the high-pressure cylinders, where four circulations are introduced, each independent of the other, viz., a circulation for the head and valves, two circulations for the cylinders, and a circulation of water within the ram itself while it is in operation. This preserves the packing of the ram and at the same time contributes largely to the cooling of the air during compression.
During the operation of the plant the initial temperatures, that is the temperatures of the inlet for each air cylinder, did not exceed 70 degrees, while the temperature for the discharge of the air varied from 290 to 350 degrees.
The mechanical efficiency of the plant, that is the ratio of the indicated horse-power in the steam cylinders to the I. H. P. of the air cylinders, was 85½%, which is quite high, considering the fact that the machines were not designed for extra economical use, the idea being to provide for the Government something that could be operated easily and which was not easy to get out of repair.
After passing the intercoolers the air is delivered into 24 storage tanks, each 16 inches in diameter by 24 feet long, containing about 650 cubic feet.
These tanks are connected with the firing manifolds. These manifolds are of complex construction, designed so as to admit the air to any or all of the guns and to admit the air to any or all of the storage tanks.
The air in the storage tanks is maintained at 2000 lbs., while the air delivered to* the storage tanks of the guns is at 1000 lbs. pressure.
The guns themselves are very interesting in their character. They weigh about 70 tons each, above their foundations, are 50 feet long by 15 inches in bore. They can fire projectiles of any caliber from 8 to 15 inches, the difference in caliber between the full and the sub-caliber being made up by wood pistons in four sections which surround the projectile and which fly off immediately upon leaving the gun. These projectiles vary from ix feet long and 15 inches in diameter for the full caliber to 8 feet long and 8 inches in diameter for the sub-caliber. The former carry 500 lbs. of dynamite explosive and the latter about 100 lbs.
The guns are easily traversed around the whole 360 degrees of circle, by an electric motor placed within one of the supports of the gun, and the connections of this motor are so arranged that it will also operate the mechanism for elevating and lowering the muzzle. The gun is ranged from o to 35 degrees, which is considered ample for all ordinary purposes. The greatest range obtained with the 8-inch projectile, carrying 100 lbs. of dynamite and which flies under a loss of pressure of about 100 lbs., was 5000 yards and slightly over. This may be considered the maximum flight for usual purposes. The 10-inch is proportionately less, and the 15-inch projectile, which carries 1000 lbs of dynamite and weighs 1100 lbs., has a range of from 2000 to 2500 yards. All of these projectiles may be thrown accurately, in fact there is no reason why, with the same pressure, the same amount of air wasted in the throwing of the projectiles, the same weight of projectile, and the same character of projectile, the atmospheric conditions being the same, it should not land practically in the same place. The results at Fort Point demonstrated this. The 8-inch projectiles were thrown from 5000 to 5070 yards, and were placed in the target, 70 yards in length by 30 yards in width, which far exceeded the Government requirements.
The material used in these projectiles is nitro-gelatine. The whole projectile is of an intricate mechanism, and has provisions made for exploding the charge either by direct impact, side impact, or by a delay of from one to three seconds. These projectiles are expensive, probably costing $1000 each, and their capacity for destruction is fully proportional to their expense.
In the test at Fort Point the 15-inch projectile at 2000 yards threw up a column of water 350 to 400 feet higH and 100 feet in diameter at the base, showing conclusively that it would be amply capable to destroy, within a range of 100 feet, the largest man-of-war.
The boilers which actuate this plant were manufactured by the Chandler & Taylor Co., of Indianapolis, are of about 500 H. P. capacity and are operated under forced draught, the idea being to keep the stacks low enough to be invisible from the bay. All of the fans which furnish the forced draught are each capable of furnishing 13,000 cubic feet of free air per minute to the grates. The boilers are fed by Deane duplex steam pumps, which are reinforced by sets of injectors.
The dynamo is operated by an Armington & Simms engine, of about 50 H. P. The dynamo is capable of furnishing 300 amperes, at 125 volts. The dynamo was manufactured by the Electrical Engineering Co., of this city, and is first-class in every respect. It also furnishes about 50 lights for the engine-room and offices during the evening.
The compressors and guns have exceeded all the requirements exacted by the Government. There was not one hitch or delay during the tests, excepting those caused by the weather, and judging from expressions, the entire Department feel that they have in these guns and the machinery to operate them a most efficient and satisfactory plant.
Shortly after noon on January 2, 1896, a series of explosions occurred at 309 N. Second Street, St. Louis, through which six lives were lost, a large number of persons injured, three buildings destroyed, and much other damage effected. From the account in the St. Louis papers, kindly supplied us by Prof. Sanger, it appears that a quantity of fireworks, of an estimated value of $8000, were stored in the building and that they were in the custody of Mr. H. B. Grubbs, to whom they had been consigned by Detwiller & Street, of New York, with a factory at Greenfield, New Jersey. The explosions originated in a fire, the cause of which was undetermined, but which was attributed to rats, and there were three successive explosions. The effect of the explosions was noticeably local and believed to be unlike the effect produced by a gunpowder explosion. For this reason the damage done was attributed to the explosion of “fire-crackers” of the variety known as “cannon crackers,” “up-to-date crackers” or “dynamite crackers,” and which were popularly supposed to contain dynamite. From the reports of the testimony before the coroner it appears that there were about 1000 boxes of Chinese and American cannon crackers in store, the largest of the latter being 15 inches long by 2 inches in diameter and having a 1-inch bore.
Five samples of fire-crackers taken from the wrecked building were submitted to Prof. Charles R. Sanger, of Washington University, for analysis, and he testified that the composition in the “up-to-date” fire-crackers consisted of 74 parts potassium chlorate, 24 parts sulphur and 2 parts charcoal or some other composition of carbon; that the charge in the large cracker was 150 grains and in the small one 10 to 12 grains; that the charges were confined by a tamping of clay; that the composition was fired by friction and by percussion; and that, in his opinion, if a considerable number of these fire-crackers were exploded they would cause others near them to explode.
From the St. Louis Republic of January 4, 1896, it appears that no law existed governing the storage of such explosives. This is evidently another example of spontaneous explosion due to contact of a chlorate with sulphur.
On December 6, 1893, an explosion of a cylinder of coal gas occurred on the wharf of the New Jersey Steamboat Co. at Albany, N. Y., by which two men were killed. Suits for damage were brought by the heirs of each of the deceased, the evidence being identical, but the plaintiff and the judge being different in each of the two cases. In the first case the plaintiff won, in the second case the plaintiff was non-suited and lost. Both cases were appealed, and in each the defendant won. Both cases were again appealed to the court of last resort, and through the courtesy of Dr. W. P. Mason we are in receipt of the plaintiff’s brief in the case of Mary Egan vs. N. J. Steamboat Co. From this we learn that the cylinder was of steel; that it was seven inches in diameter by fifty-four to fifty-five inches long; that it was filled with illuminating gas made by mixing water gas and ordinary coal gas in such proportions as to produce a mixture of nearly equal parts of hydrogen and carbon monoxide, with sufficient heavy hydrocarbons added to make it luminous; that the cylinder weighed about 100 lbs., and that the weight of the added gas was so small that, it is claimed, a laborer handling one of these cylinders could not tell, except by testing it, whether it was full or empty.
The counsel makes the points, among others, that the defendant was guilty of culpable negligence, under the common law, in directing the intestate to handle this cylinder, in its then condition, charged with gas to a high pressure, under the circumstances of the case; that he was guilty of violation of Sec. 4472 of Revised Statutes U. S., forbidding the transportation of nitroglycerin and like dangerous articles by passenger steamers; and that illuminating gas is an explosive burning fluid like the coal oil, camphene, benzine, and others cited in the statute. He cites the opinions of courts deciding that “gas” is an explosive. It is remarkable what confusion of thought regarding the properties of matter exists in the minds of otherwise intelligent men.
The exciting cause of this explosion has not been ascertained. It is stated that the explosion occurred just as the laborer, who carried the cylinder on his shoulder from the steamboat to the storehouse, was laying it down on the storehouse floor.
S. J. von Romocki presents in two stout volumes his “Geschichte der Explosivstoffe;* volume I being devoted to the history of the chemistry of explosives, the technology of explosives, and to military and naval mining from their beginning up to the present century, while volume II treats of the history of smokeless powders up to the present time.
The extent of ground covered may be judged from the following titles of the chapters in volume I: War-fire up to the introduction of saltpeter; the first explosive; explosives in the Occident; the Fire-book of Marcus Graccus; the Fire-book in Konrad Kyeser’s “Bellifortis”; the Fireworks-book and the explosives of the 15th century; Johannes de Fontana’s Sketchbook; the beginning of sub-terra mines; the progress in the technology of explosives in the 16th century; the powder-ship before Antwerp in 1585; petards and marine mines; explosive missiles with flint and steel igniters; moveable and controlled torpedoes before La Rochelle in 1628; further inventions of Cornelius Drebbels; rocket and fish torpedoes. Copious extracts, in the original languages, are given from the Latin, Greek, Arabic, Chinese and other manuscripts and books. The chapters of volume II bear the following titles: Saltpeter powder with varying proportions of sulphur; chlorate powder; ammonium nitrate powder; picrate powder; xyloidine; the discovery of gun-cotton; guncotton up to its abandonment' in Austria; nitro-cellulose from its revival in England to the discovery of the Vieille powder; the nitro-cellulose powders of the present time.
The work is a scholarly production, and bears evidence of the most painstaking research into the literature of the subjects treated of, while the numerous references are given with great detail and exactitude. The volumes are illustrated with 140 cuts, those in the first volume being of especial interest.
"Cellulose, an Outline of the Chemistry of the Structural Elements of Plants, by Cross and Bevan,” * is the most recent and most valuable work on this subject that has appeared, and it contains so much new and original matter that all who are engaged in manufactures in which cellulose in its various forms is employed, as for instance in the production of the explosive cellulose nitrates, should be familiar with its contents.
Apropos of the use of these nitrates in the manufacture of smokeless powders the authors remark: “These industries are in a highly developed condition, the manufacture being carried on with the greatest precision, on the basis of an extensive empirical knowledge of the properties of the products. It must be admitted, however, that, in the absence of any precise knowledge or even accepted theories of the constitution of the cellulose nitrates, there remains a vista of progress to be opened out by the solution or partial solution of this important problem.”
“Coal Dust as an Explosive Agent, as shown by an Examination of the Camerton Explosion,” †by Donald M. D. Stuart, develops the theory that a colliery explosion, in which coal-dust is the principal agent, comprises numerous local explosions separate in time and in space, at irregular intervals, where the normal supplies of atmospheric oxygen are greatly increased, and is caused by the explosive combustion of accumulations of hydrogen gas, derived from the coal-dust in the antecedent spaces, by a series of chemical actions of constant sequence, which produce heat for regeneration without auxiliary intervention, and are constantly reproduced along the path of the coal-dust under the conditions named.
An elaborate discussion of Mr. Stuart’s theory and data will be found in Trans. Am. Inst. Mining Eng., 24, 905-917; 1895, to which Mr. Stuart replies in a very satisfactory manner in a paper read at the meeting, February, 1896, and to be published in volume 26.
Crosby, Lockwood & Son, London, announce the appearance of “Nitro-explosives,” by P. Gerald Sanford. 270 pp. 1896; and Hirschfeld Bros., New York, announce “The Origin and Rationale of Colliery Explosions,” by Donald M. D. Stuart.
*As it is proposed to continue these notes from time to time, authors, publishers, and manufacturers will do the writer a favor by sending him copies of their papers, publications or trade circulars. Address, Columbian University, Washington, D. C.
* Rept. H. M. Insp. Exp., 1890, p. 35; Special Report No. 94.
* Phil. Trans., 165, 61.
* Noble, Internal Ballistics, 33; 1892, and Proc. Roy. Soc., 52, 128.
*Noble and Abel, Phil. Trans., 165, 110.
*Compare Noble and Abel, loc. cit., p. 109.
* Large 8vo. Vol. I., 394 pp.; Vol. II., 324 pp. Berlin: Robert Oppcn- heim (Gustav Schmidt), 1895.
* London: Longmans, Green & Co., 1895. 8vo. 320 pp., 13 plates.
† New York: Spon & Chamberlain, 1894. Sm. 4to. 103 pp., 7 large plates.