As the subject of firing high-explosive shells from great guns is engaging the attention of many at the present time, I have thought it well to follow the advice of my friend Professor Munroe, who has himself published so many valuable "Notes on the Literature of Explosives," and to place on record a correct history of the first successful attempts ever made in the United States (so far as known) to fire dynamite in shells from great guns, together with my views on the subject as officially expressed at intervals during the last twelve years.
These experiments prove, so far as a limited number can be relied on to prove anything
1st. That dynamite can be safely fired from great guns in shells without extra precautions being taken to reduce the shock of discharge.
2d. That the ordinary Bormann fuse will explode dynamite shells.
3d. That howitzers or guns of small calibre can be employed to throw cases of dynamite or gun-cotton against vessels regardless of the ordinary devices used to protect ships from torpedo attacks.
One of the chief sources of apprehension in the use of high explosives for charging projectiles arose from the fact that it was believed that the highly sensitive fulminate-of-mercury fuse was necessary for its complete explosion.
On the 18th of May, 1874, while at the Torpedo Station, certain experiments—made, I am quite sure, at the suggestion of Professor Farmer—seemed to prove that a simple gunpowder fuse would detonate nitroglycerine and dynamite if either the gunpowder or the high explosive were confined in a strong metallic case. The following are the experiments referred to:
1st. Some yarns were soaked in nitroglycerine, and the platinum wire of an ordinary station fuse connected to a Farmer machine was laid on them. The wire was melted and the yarns were set on fire, but the nitroglycerine did not explode.
2d. The platinum wire of a fuse was put into nitroglycerine. The wire was melted, but the nitroglycerine neither burned nor exploded.
3d. Same as No. 2, except that the wire was longer. The nitroglycerine neither burned nor exploded.
4th. Two pieces of No. 36 platinum wire two inches in length were placed in a dish containing nitroglycerine. The wire was melted as usual by the use of the Farmer machine, but the nitroglycerine was neither set on fire nor exploded.
5th. One inch of platinum wire was laid on some yarns saturated with nitroglycerine. The wire was melted and the yarns were set on fire, but there was no explosion.
6th. One and a half ounces of nitroglycerine were placed in an iron tube, and a Stowell metal fuse of rifle powder was used. The nitroglycerine detonated.
7th. One and a half ounces of nitroglycerine were put in a tin tube, and an ordinary station fuse of rifle powder, in a wood case, was used. The nitroglycerine detonated.
8th and 9th. Same fuse, with same amount of nitroglycerine in a paper case, was used. There was no explosion of the nitroglycerine.
10th. Same fuse, same amount of nitroglycerine in a tin case, was used. Nitroglycerine detonated.
11th. A copper-case fuse with mealed powder and same amount of nitroglycerine in a paper case was used. Detonated.
12th. A copper-case fuse with mealed powder and same amount of dynamite in a paper case was used. Detonated.
The following note was made at the time of the foregoing experiments: "From these experiments it would seem that nitroglycerine can be detonated by gunpowder if either the fuse case or the case holding the nitroglycerine is made of some metal and very strong. Thus it seems as if we could do away with the fulminate fuse, which is rather dangerous to make."
The result of these experiments gave a new impulse to a desire which I had long entertained of ascertaining whether or not shells filled with dynamite could be safely fired from great guns. Accordingly, on the 9th of June, 1874, I submitted to Captain (now Rear-Admiral) Edward Simpson, U. S. Navy, who commanded the Station, a list of experiments which I desired to make in order to ascertain the following facts: 1. Will the shock of a fulminate fuse detonate nitroglycerine, the latter being placed in an inner tube and the fuse between the inner and outer tube, both tubes being of iron? 2. Will a gunpowder instead of a fulminate fuse produce the same effect? 3. Will the shock transmitted through the metal case containing the nitroglycerine have any effect on the explosive, the tubes being arranged as before, but the one containing the explosive being of copper or tin? 4. Will the effect be the same when dynamite is substituted for nitroglycerine?
Should these experiments warrant me in so doing, then I desired to make the following experiments: 1. To fire from a musket or rifle a brass tube or metallic case filled with dynamite. 2. To put nitroglycerine or dynamite in an ordinary shell and explode it with an ordinary time fuse. Should this not explode the charge, (3) to try the same kind of fuse with an extra quantity of powder placed in the shell near the fuse. If this should detonate the charge in the shell, (4) to fire a shell filled with dynamite from a howitzer, firing it against a rock, if possible, so that, should the shock of the discharge fail to detonate the dynamite in the shell, it could be seen if the impact of the shell against the rock would do it. 5. To fire an ordinary shell filled with dynamite and fitted with ordinary service fuse. And (6) to try the same with percussion fuse. Captain Simpson took upon himself the responsibility and cheerfully granted the request. I must here mention that Professor Hill, the expert on explosives, who was absent from the station on the 18th of May, while possibly willing to admit, in view of what had been done, that gunpowder fuses might at times detonate dynamite and nitroglycerine, insisted that they could not be relied on to do so at all times and under all circumstances. His opinion proved to be correct, as shown some months later, when it was attempted to detonate unconfined dynamite with a gunpowder fuse.
The following are the experiments as conducted, the fuses used being exploded by means of electricity, using the Farmer machine:—
EFFECT OF A FULMINATE-OF-MERCURY FUSE (20 GRAINS) ON NITROGLYCERINE IN A METALLIC TUBE PLACED INSIDE ANOTHER TUBE WITH FUSE BETWEEN.
June 15, 1874. No. 1. Inner tube made of one-inch iron gas pipe containing one ounce of nitroglycerine. Pipe plugged with wood at one end. Outer tube of good iron, half inch in thickness. Fulminate-of-mercury fuse between. Top of inner tube not plugged. Detonated, throwing the whole mass a long distance into the water, and breaking the small rock on which the tubes were placed.
No. 2. Outer tube of one-inch iron gas pipe. Inner tube of brass one-sixteenth inch thick; length, one and a half inches; diameter over all, half inch, containing quarter ounce nitroglycerine. Fulminate-of-mercury fuse between. Detonated.
No. 3. To see the effect of an unconfined fulminate fuse on the metal of a tube. In a brass tube one-sixteenth inch thick, three inches long, three-quarters inch diameter, open at both ends, placed a fulminate-of-mercury fuse. Exploded, tearing the tube, although there was considerable space around the fuse and at the ends of the tube for the escape of gases.
No. 4. Same as No. 2, with same effect.
EFFECT ON GUNPOWDER FUSES.
June 16th. No. 5. In an ordinary iron gas-pipe tube, plugged tightly at one end, placed a small brass tube containing quarter ounce dynamite. Fired with mealed powder fuse, metallic case, which was jammed in between the two tubes. The fuse alone exploded, blowing out the inner tube.
No. 6. In a large iron tube, plugged at one end, placed a large brass tube one-eighth inch thick, six inches long, one and a half inches diameter, containing one ounce of dynamite. Cap screwed on one end and the other end soldered. Fuse of mealed powder, metallic case, jammed between the two tubes. Fuse alone exploded, forcing out the rear plug of the large outer tube about one inch.
No. 7. Used same large iron tube, inside of which placed a large brass tube, as before, containing one ounce of dynamite. Used DE3 igniter (rifle powder and wood case) and filled outer tube with sand. Fuse alone exploded, throwing out the sand.
No. 8. In a brass tube three inches long, three-quarters inch diameter, put a half ounce of dynamite. Plug the ends and put this in the large iron tube. Put in DE3 igniter and a charge of powder half as great as is contained in a DE4 fuse, or from three to four charges for an ordinary musket. The igniter was placed between the tubes and the powder poured about it, while the remaining space was filled with sand. Exploded, driving out the rear plug and the sand, leaving the tube of dynamite uninjured inside.
No. 9. Used same inner tube, placed in an iron tube of ordinary one inch gas pipe; space so small that with the insulated leading wires in the iron tube the inner one had to be forced down. Placed the same amount of powder as before in the outer tube at the base of the tube containing the dynamite. Fuse of mealed powder, metallic case. Fired at a rock a few feet distant. The end of the outer tube was torn, but the rock showed signs of having been struck. An end piece of the brass tube was picked up. The sound of the explosion was loud, but I could not tell whether the dynamite detonated or not: it certainly did not while in the iron tube, as the tube was not torn where the dynamite had been, but only where I had placed the large charge of powder. No sign of a great disturbance was discovered; still, judging from the result of the next experiment, it is possible that the dynamite may have detonated after having hit the rock, as a plug was protruding nearly three-quarters of an inch from the tube.
No. 10. Used same sized brass tube containing half ounce of dynamite. Put this in an iron gas-pipe tube six inches long and one inch in diameter. Used an ordinary charge of rifle powder and a DE3 igniter. A wooden plug projected from a brass tube a good half inch. A board was placed four feet in front. Iron tube plugged at rear end. When fired much of the gas of the powder escaped at the rear, driving out the plug. The tube of dynamite entered the target one-fourth of an inch, and when picked up was very hot, with the hard oak plug driven entirely into the tube, a little counter-sunk, and nitroglycerine was boiling out through the pores of the plug. As the force exerted by the powder on the brass tube was not so great in this case as in No. 9, and as the target was a rock in the former case, I am inclined to the belief that the heat generated by impact may have detonated the mass in the preceding case (No. 9).
These experiments showed the necessity of having some kind of a gun, and of doing away with rough tubes and wooden plugs. Accordingly, a gun was made of wrought iron, calibre .75 inch, depth of bore 12 inches, thickness of barrel half inch; the whole firmly bolted to a block of wood. From this I fired projectiles consisting of brass tubes one-sixteenth inch thick, one and three-quarters inches long, and five-eighths inch in diameter. They contained a quarter ounce of dynamite.
June 18th. No. 11. Used small charge of rifle powder. Placed an inch board for a target at a distance of six feet. Tube passed through the board into the water.
No. 12. Same as No. II, but with the ordinary charge of powder for a musket. Tube passed through the board and struck a rock in rear of the target. Picked up a piece of the tube. No detonation observed.
No. 13. Same as No 12, but with an increased charge of rifle powder. Target was blown down just before firing. Projectile went into the water. No detonation. Gun recoiled several feet.
No. 14. Charge of powder at least three times as great as for ordinary rifle. Tube went through the target and hit a rock, breaking off a small piece, then glanced into the water. Gun recoiled several feet.
June 19th. No. 15. Ordinary charge of powder. Fired at a rock. Tube much battered. No detonation.
No. 16. Ordinary charge of powder. Fired into a mud-bank three feet distant. Tube recovered in perfect shape, except that the soldered end came off.
No. 17. Double charge of powder. Target two and a half feet distant, set against a mud-bank. Projectile passed through the target, going into the mud-bank several inches. Found the tube torn, but the dynamite was picked up with the tube. Gun recoiled seven feet.
No. 18. Double charge of powder, tube of copper, containing one-eighth ounce dynamite. The tube passed through a board, struck a rock in the rear, then doubtless glanced into the water, as it could not be found.
No. 19. Same as No. 18. Fired through the target into the bank.
Experiments with 24-Pounder Shells at Rest.
These were exploded in the bomb-proofs on Rose Island.
June 22d. No. 20. Put four and a half ounces of dynamite into a 24-pounder shell. Used ordinary Bormann fuse, with an additional brass magazine containing a small rifle charge of powder. Placed in bomb proof on Rose Island where there was much rubbish. Detonated, tearing the shell into many fragments, twenty-seven of which were picked up from the rubbish. Made a large hole in the ground.
June 25th. No. 21. In another bomb-proof, where there was not so much rubbish, exploded between three and four ounces of dynamite in a 24-pounder shell placed on a wrought-iron slab 4 feet by 5 inches by 1 inch. Used a small additional magazine of powder. Picked up fifty-eight pieces of shell and counted forty-nine marks on the walls of the bomb-proof. The iron slab was somewhat bent, and the brick and stone under it were crumbled. A piece of the masonry running up the bomb-proof and projecting out eight inches, one foot in width, distant one and a half feet from the shell, was cut out a foot in depth.
No. 22. Put four ounces of dynamite in a 24-pounder shell, Bormann fuse, with no additional charge. Placed shell on same iron slab three inches from the wall. Detonated, bending slab. Tore quite a large hole in the solid masonry to a depth of six inches. Picked up seventy-nine pieces of shell.
No. 23. Put four ounces of dynamite in a 24-pounder shell, which was laid on fourteen bricks placed one on the other. Shell rested against an iron slab, which was itself against the wall, bringing the shell three feet from the ground. There being no fuse at hand for this shell, a small brass magazine was used. Slab was considerably bent by the explosion. The stone in the masonry against which the slab rested showed marks of having been shattered, but no large pieces came out. All the bricks underneath were broken into fragments. Fifty-six pieces of shell were picked up.
No. 24. Put three and a half ounces of dynamite in a 24-pounder shell, Bormann fuse only. Placed shell as in No. 23. Broke all the bricks upon which it rested. Bent slab, throwing it quite a distance, and jarred the masonry against which it was placed.
No. 25. Put three and a half ounces of dynamite in a 24-pounder shell, Bormann fuse only. Shell placed on a slab of iron, which was laid on the ground. Detonated with same effect as usual.
No. 26. Put what was left of the dynamite which I had taken to the island, about two ounces, in a 24-pounder shell, and used an old Bormann fuse the chamber of which had been cut into. The fuse alone went off. Probably part of the powder had shaken out of the chamber of the fuse, as it was a very old one and had been cut a long time. This and the very small quantity of dynamite in the shell—leaving so much room—were the causes, doubtless, of failure.
No. 27. In the same shell screwed a small brass magazine of powder. It now detonated, and threw the iron slab, weighing 80 pounds, which had been placed against the shell, thirteen feet and shattered corner of bomb-proof to some extent.
Experiments at Firing Dynamite Shells from a 24-Pound Howitzer.
June 30. A 24-pounder howitzer was transported from this station to Rose Island and mounted in one of the bomb-proofs. The cartridges used were the ordinary service charges, and the gun was fired in every respect as it would have been in service, except that the vent was filled with powder, which was ignited by electricity. No measures were taken to reduce the shock of the discharge on the projectile in any of these trials.
No. 28. From a 24-pounder, fired a shell nearly full of dynamite into a thick wall thirteen feet distant. The shell exploded on impact, making a hole in a solid rock seven inches in depth, which spread out considerably. The rock was pulverized. Picked up seventy-five pieces of shell.
July 2d. No. 29. Filled a 24-pounder shell loosely with dynamite and fired it into the wall of bomb-proof about forty feet distant. Detonated on impact, scooping out a hole in the brick, stone and mortar to the depth often inches.
No. 30. Then, to compare this effect with that of an empty shell, fired an empty 24-pounder shell into the wall at same distance. Penetrated fourteen and a half inches into wall, making a round hole instead of a spreading one. The shell broke, but half of it was taken out in one piece.
No. 31. Fired at same distance a 24-pounder shell loosely filled with dynamite. Detonated on impact, making a spreading hole like the first (No. 28), and penetrating about the same distance.
The following note was made at the time: "It seems from these (experiments) that dynamite detonates at the instant of impact, and so instantly that the shell does not penetrate as far as it would if it had no charge in it; but the shattering effect is greater."
Firing up the Bay.
July 8, 1874. Fired a 24-pounder shell filled with dynamite from bomb-proof on Rose Island. Pointed the gun up the Bay. Did not cut the fuse. The shell did not explode, but struck the water a mile distant (estimated).
No. 33. Fired a 24-pounder shell filled with dynamite, using Bormann fuse cut at four seconds. A half gale of wind was blowing in the direction of the flight of the shell. It was also cloudy. Several disturbances were noticed in the water just beyond the island, probably pieces of sabot. The smoke attending the bursting of the Bormann fuse was so slight in amount it was not seen, owing to the peculiar state of the weather. The sound of the projectile through the air was heard for some time, as usual. Small pieces of shell striking the water in such a rough sea could not be seen at a great distance.
July 9th. No. 34. Fired a 24-pounder shell filled with dynamite, fuse purposely left uncut. Gun given almost extreme elevation. The shell went a long distance up the Bay and struck the water without exploding. Sea perfectly smooth; no wind.
July 15th. No. 35. Put fourteen ounces of dynamite in a 24-pounder shell and fired it up the Bay. The Bormann fuse had been in the shell several days, and, though cut at four seconds, it did not burn. I had added a small magazine of powder, which did not ignite. The shell struck the water a long distance up the Bay without exploding.
No. 36. Put fourteen ounces of dynamite in a 24-pounder shell, Bormann fuse, with a very little extra powder, to show more clearly when the shell should burst. Fuse cut at four seconds. Shell burst at proper time.
No. 37. Put fourteen ounces of dynamite in a 24-pounder shell. Used Bormann fuse only, which was cut at three and a half seconds. Shell exploded at the proper time, scattering pieces to the right and left for a great distance. Not a grain of powder to help the fuse. The fuse made very little smoke.
Brief Recapitulation.
The first two and the fourth experiments were made to see what effect the shock of a fulminate- of-mercury fuse would have on nitroglycerine when separated from it by a diaphragm of metal. It was found that the fulminate fuse containing twenty grains would tear through the metal employed, hence all further experiments with the fulminate fuse ceased. The next series of experiments showed that in no case did the shock of a powder fuse, whether with a metallic or wooden case, detonate nitroglycerine when it was separated from the fuse by a metal diaphragm.
Again, in no case was there a premature explosion in all the experiments with the wrought-iron gun, although the best rifle powder was used with varying charges.
Again, in all the experiments made with the shells at rest, it was shown that the dynamite contained in them was exploded by the use of a gunpowder fuse, with or without an additional priming of powder, and the force of the explosions seemed to me to be much greater than it would have been had the shells been filled with powder instead of dynamite. I am sorry, however, that I did not explode one filled with powder, in order that the different effects of the explosions might have been compared at the time.
Again, the result of the howitzer experiments in firing shells charged with dynamite was very satisfactory. There were no premature explosions. Some of the fuses were left uncut on purpose, in order to observe the extreme flight of the shell. One shell was not seen to burst, neither was it seen to strike the water, but this is easily accounted for from the fact that dynamite makes little or no smoke when it detonates, and at the time referred to a half gale of wind was blowing, clouds obscured the sky, and the water was very rough. The flight of the shell was heard for a short time after it left the gun.
Having exhausted the available stock of shells at the Torpedo Station, experiments ceased, and on the very day of firing the last shell my detachment was received at the station. In a personal interview with the Chief of the Bureau of Ordnance soon after this, I urged that the experiments be continued on a larger scale, and asked that he would, at least, have a XV-inch shell filled with dynamite hung against an iron target and exploded. He gave some encouragement that this would be done, and a month later the late Commander Marvin, U.S.N., at that time, I think, in charge of the experimental battery, told me that it was to be done; but doubtless other things interfered.
These experiments were made in 1874. I then thought that this question was, perhaps, the most important one connected with ordnance ; for we were far behind other nations in respect to ships and great guns, and should it have proved practicable to fire dynamite shells, our smooth-bore guns of large calibre could have been used, and at a bound we would have nearly regained our old position of superiority; for the armor of vessels was not so thick then as now, great guns were not so powerful, and machine guns had not reached their present state of development; but nothing further was done. Four years passed, and in 1878 I was again at the Torpedo Station, Captain K. R. Breese, U.S. Navy, commanding. Finding that my former experiments could not be continued, I requested permission to pursue another branch of the subject, and addressed a communication to Captain Breese as follows:
Torpedo Station, Newport, R. I., June 29, 1878.
Sir—Can cases filled with nitroglycerine, dynamite, or gun-cotton be fired from great guns in safety to the guns and to those operating them? If either of them can be used in this manner, it seems to me the whole subject of torpedo warfare is immensely simplified.
To my mind the solution of this question is of more importance than that of any other connected with the subject of torpedoes. Four years ago I carried on a series of experiments at this station which, so far as they went, demonstrated that shell filled with dynamite—at least such dynamite as was then provided—could be fired from guns. My experiments were limited to the 24-pounder howitzer. The Chief of the Bureau of Ordnance did not see fit to encourage further experiments in that direction, and there the matter ended. That dynamite (or similar mixture) is regarded as comparatively harmless, is shown from the fact that it is transported by rail all over the country, and is used extensively in mining, etc. If the Whitehead and Harvey torpedoes are intended to be charged with gun-cotton or dynamite, these explosives will have to be carried in the ships from which these torpedoes are manipulated; hence, the objection cannot be raised by advocates of the Whitehead and Harvey that the danger of using these explosives on board ship is too great.
I now propose a plan which, if practicable, will enable us to use dynamite, nitroglycerine, or gun-cotton from the ordinary ship's launch, and I therefore respectfully request that I may make a few preliminary experiments with a 24-pounder howitzer.
I wish to see if I cannot throw a weight of from fifty to one hundred pounds a hundred feet or more without undue strain to the gun. If this can be done, I think torpedoes may be fired or projected against a vessel from an ordinary launch, and thus the difficulty of reaching a vessel protected by nettings, booms and other obstructions will be overcome. Not only this, but the launch could run at full speed past the broadside of the vessel and be out of harm's way by the time the torpedo exploded, for the gun could be trained broad off the bow, or even well-nigh abeam, when fired. I grant that the explosions might not always be at or below the water line, but let fifty pounds of dynamite explode against the vessel at night, it could not fail of demoralizing the crew, and a second attempt could be made before order was restored. I enclose with this a summary of my experiments made with dynamite, referred to above.
Very respectfully, etc., etc.
Captain Breese thought well of the idea and granted the request, although it interfered somewhat with the regular work at the station. And so soon as I had satisfied myself of the practicability of the scheme by actual practice, I reported it, in order that, should the Bureau of Ordnance see fit, the experiments could be carried on with the Bureau's approval and with greater facilities. At the suggestion of Captain Breese I addressed the Bureau on the subject, and as an account of the experiments is contained in the letter, a copy is here inserted:
Torpedo Station, Newport, R. I., August 8, 1878.
Commodore Wm. Jeffers,
Chief of Bureau of Ordnance, Washington, D.C.
Sir:—At the suggestion of Captain Breese, commanding this station, I beg to submit the following on the subject of torpedoes:
In July, 1874, I submitted to Commodore (then Captain) Simpson a report of some experiments made by me, in which from a 24-pounder howitzer I fired shells filled with dynamite. These experiments were undertaken to demonstrate that it would be safe to fire large shells or cases of dynamite, so that (I quote from the report) "wherever a large gun could be mounted, there would be a place from which torpedoes—for so we might call them—could be launched with great accuracy against an enemy, and much expense saved the Government by rendering unnecessary greatly extended fortifications and expensive torpedoes such as the 'Lay,' 'Whitehead,'" etc. This report was forwarded to the Bureau of Ordnance.
As there was no gun larger than a 24-pounder howitzer at the station, my experiments ceased after having fired successfully about a dozen shell. Last month, permission to make experiments of a somewhat similar character was kindly granted me. I wished to see if 12-pounder or 24-pounder howitzers could not be used to throw large charges of dynamite against vessels distant 50 to 200 yards, which charges should explode upon impact by means of percussion fuses. If this could be done, it would render useless as a defense against torpedoes of this class such obstructions as are now placed around vessels to protect them from the attack of torpedoes, for launches mounting one or more guns could run at full speed just outside the obstructions, and when abreast, or anywhere within 200 yards, these cases of dynamite or guncotton could be fired in quick succession without slowing the engines, or getting so near as to become entangled in the obstructions. To this end I made the following experiments:
July 12th. Made a soft-wood shaft to fit the bore of a 12-pounder. The shaft was grooved to within four inches of the inner end. It projected a few inches from the muzzle. On the outer end was secured an empty 24-pounder shell. The whole weight of the projectile was 30 ½ pounds. The charge of powder used was ½ pound cannon mixed with enough rice to preserve the original size and shape of the cartridge for the 12-pounder. Another reason for mixing rice with the powder was to make it burn more slowly. This projectile was sent as straight as an arrow to a distance of 450 feet.
Second Experiment.
July 15th. A new pine shaft was fitted to the bore as before, the inner end shod with iron 1/16 inch in thickness. Secured an empty 32-pounder shell to the outer end. Total weight 43 pounds. Charge of powder the same as before (cannon mixed with rice). This projectile made a perfect line shot, being thrown from 100 to 150 yards.
Third Experiment.
Same as above with same result.
Fourth Experiment.
Fitted a shaft to a 24-pounder similar to the shaft used above. On the outer end an old cast-iron torpedo case filled with 41 ½ pounds of rice was secured. Whole weight of projectile, 99 ½ pounds. Extreme elevation on boat carriage. Much of the gas escaped on account of the imperfect construction of the shaft nevertheless, this projectile was sent 50 yards, making a perfect line shot. Charge of powder used was one pound, mixed as before with rice.
These experiments, crude as they were, satisfied me that there would be no difficulty in throwing from 25 to 100 pounds of dynamite from 50 to 200 yards, using simply the ordinary boat howitzers.
There is much room for experiment to determine the best kind of powder to be used for this purpose, the proper charge, and the best kind of shaft, as well as the best form of case in which to place the explosive. There is no doubt but that the case should be made of steel.
In order to see what effect a charge of dynamite would have on a ship's side if exploded against it, the commandant of the station had a wrought-iron slab four and a half inches thick, three and a half feet wide and six and three-quarters feet long placed in position, and a cylindrical case containing 40 pounds of dynamite was placed against the centre of the slab.
The slab was bent by the effect of the explosion .... making a clear cut in the back of the slab to the depth of four inches, extending the whole width of the slab. The lumber placed in rear of the slab to support it was badly broken. My own impression is that for general use in steam launches, cases of 50 pounds of dynamite would be sufficiently great to give satisfactory results. The cylindrical case used in this experiment could have entered the bore of an VIII-inch gun. I believe that if a slow-burning powder were used, cases of dynamite could be fired a mile with great accuracy from great guns, the projectile being set home against the cartridge and thrown as a shell. In other words, the use of the wood shaft might be dispensed with when firing from great guns. It would be interesting to know what the effect of 50 pounds of dynamite would be if exploded on the deck of an ironclad. I respectfully submit the above to the Bureau, believing it to be a matter of the greatest importance, for it seems to me that torpedoes of this character, defying obstructions placed around vessels, might in the vast majority of cases be advantageously substituted for the awkward "spar," the cumbersome "Harvey" and the expensive "Lay," "Ericsson," and "Whitehead" torpedoes in offensive warfare. I have the honor to be, etc., etc., etc.
This communication was returned to the Torpedo Station with the following endorsement:
15th August, 1878.
Respectfully returned to the Torpedo Station. The Bureau has carefully perused the communication of the 8th inst. from Comdr. A. S. Barker. The Navy is not prepared at present to carry dynamite to sea, and hitherto all experiments in firing dynamite shells from guns have been unsuccessful and useless. Upon a practically large scale, with projectiles carrying from 30 to 50 pounds, no useful results could be expected. Our funds will not admit at present of any such course of experiments. (Signed) W. N. Jeffers, Com. and Chief of Bureau.
Another four years pass, when I again have an opportunity to refer to the subject officially, in a communication to the Hon. Secretary of the Navy, dated Nov. 27, 1882, in obedience to an order to make a report upon the monitor Montauk, which I had commanded, and to offer suggestions for improvements. After having suggested a few changes—among others, that the guns be given an elevation of at least twelve degrees, by putting in improved gun-carriages, etc.—I continued substantially as follows:
In this connection I respectfully submit what I consider to be the most important change of all, and one which warrants careful attention— viz.: that in place of, or rather in addition to, the ordinary shell, there should be furnished projectiles of a peculiar kind filled with a violent explosive. They might be termed "torpedo shells," a name already used to designate certain projectiles thrown from Krupp's mortars. They should be made of steel, and for a XV-inch gun should have a capacity for at least 100 pounds of explosive.
Eight years ago, while at the Torpedo Station, with the approval of Commodore Simpson, commanding the station, I fired from a 24-pounder howitzer several shells filled with dynamite. The experiments, though limited in number, were successful, but the Chief of Bureau of Ordnance at that time did not think it advisable to have them continued on a larger scale.
Since that date Nobel's gelatine has been added to the list of explosives, and, from reports, it is admirably adapted for use in this manner. A XV-inch gun could throw a shell containing 100 pounds of gelatine a distance of two miles. Should the shell strike the solid armor of an ironclad, the explosive would probably detonate, but, whether it would or not, it would be easy to fit percussion and time fuses. Were the "monitors" thus supplied, foreign ships would scarcely care to venture within range of our guns, and beyond that range, provided an elevation of 12° could be obtained, they might fire at our turrets all day without making a satisfactory hit. The cross-section of these turrets is less than 25 feet by 12 feet, or but little larger than an ordinary target.
It is estimated by some English authorities that not more than one shot out of fifty hits a target in ordinary target practice at sea, and the usual distance of a target from a ship is much less than two miles. If, then, but one shot in fifty should hit the turret, the chances are that three-fourths of those hits would be glancing blows, owing to the curved surface of the turrets. All experience proves how difficult it is to hit a small object at sea when more than a mile distant. A few experiments, at comparatively small expense, would determine the practicability of using such shell, and also show the effect they would have against iron targets.
I am as thoroughly convinced that these projectiles will be used as I am that there will be future wars; it is only a question of time. Already Krupp is dropping "torpedo shells" from his light mortars with great accuracy and effect, but in actual war they will be filled with gelatine or other explosive instead of powder. Why should not the United States be the first to make the change, if it prove practicable, and utilize her big smooth-bore guns? It would not only greatly increase the efficiency of the "monitors," but also add to the importance of our coast fortifications.
That these were efficient vessels during the late war, hundreds of shot marks on turret and hull attest, and should the suggestions contained herein be adopted, I doubt not they will again be made efficient and formidable, and will be invaluable for the protection of our harbors against attacks by foreign navies. I am, Sir, etc., etc., etc.
Thus for twelve years, or since making the experiments in 1874, I have many times privately, and several times officially, referred to them and urged the importance of the subject.
I have frequently in this paper used the word "detonated" when referring to the explosion of dynamite and nitroglycerine. It has been questioned of late whether the effect of dynamite, if exploded with a gunpowder fuse, is ever as great as when a fulminate-of-mercury fuse is used—in other words, whether complete detonation actually takes place. It is further questioned whether dynamite or gun-cotton shells, bursting alongside an armored vessel, would materially injure her.
Doubtless the first question will soon be definitely settled by experiments at the Torpedo Station, and if it shall be proved that dynamite and gun-cotton shells will not be effective when exploded alongside an armored vessel, they must necessarily be effective when dropped on her decks from mortars. I myself am inclined to believe that the moral effect of high-explosive shells will always be great, and that they will also have a material effect on the vessel when exploded alongside.
My prediction in regard to the use of these shells is already being fulfilled, if the reports are true which come to us from abroad, and I am glad that our own Government is taking a deep interest in the subject. Congress has appropriated, or, it is said, will appropriate $350,000 for the construction of a pneumatic dynamite gun-vessel which shall carry guns guaranteed to throw projectiles containing one hundred pounds of dynamite, or other high explosive, a distance of at least one mile. Dare any one assert positively that our XV-inch guns cannot do even better than that?