Improvised explosive device

“ A groove is cut around the stick about 8” from the handle end, to which is wired three pieces of cotton about 11⁄2” x 24” long. These act as streamers and tend to keep the business end of the bomb forward in its flight.
Note: The idea of the explosive being used in the dummy bombs is to accustom the men to handling explosives, the lighting of fuses and gauging of the time required per inch for a service fuse to burn, at the same time not sacrificing distance and accuracy in throwing. ”

“ Gas-shells are mixed in with shrapnel and high explosives, and when thus employed are often very deadly. Fired alone, they are distinguishable because of their peculiar explosive sound; but, when they are sent over in a general bombardment, the only way to be sure of escaping them is to use the mask continuously. ”

“ For this reason it is easy to tell from the character of the fragments of a projectile whether or not a high explosive or an explosive of inferior power was employed, that is to say, whether or not the explosion was of high order or of low order.
There is one false belief about the action of high explosives that has been about the hardest of any to kill, and the cost of killing it has been very expensive. Furthermore, it possesses more lives than the proverbial nine-lived cat. ”

“ As a matter of fact, airships are capable of working comparatively small damage by dropping bombs, unless the bombs can be made to hit and penetrate the object struck before exploding, for the reason that, unless confined, explosives have but little effect.
When a mass of high explosive is detonated upon a firm, resisting body, like the earth, or the deck of a battleship, or armor-plate, the effect is to rebound from the resisting body with small result. ”

“ As the time required for the projectile to [6] be thrown from a twelve-inch cannon is only about the sixtieth of a second, sixty of these huge guns could be placed side by side and fired by electricity one after the other, while grandfather’s clock is making but one tick.
Our ideas of duration are but relative. We have seen that the combustion in a cannon, though very rapid to our senses, is actually very slow indeed as compared with the much more rapid combustion of a high explosive ”

“ It is believed that great improvements can be made in the shape of the bomb and in the powder charge, which will result in much longer range and high efficiency, while in no way increasing the weight of the bomb or decreasing the rate of fire. These last two weapons were used during the World War, and will be very extensively used in the future for firing high explosive, phosphorus, thermit and similar materials that non-technical troops might handle. ”

“ The exact opposite is the truth. When a mass of explosive is detonated, it is converted practically instantly into a ball of incandescent gases and vapors under very high pressure. When confined the gases act to disrupt their container.
When a large steel projectile is charged with a high explosive, like picric acid, and the explosive detonated, the walls of the pro [10] jectile are not only broken but they are also torn, twisted and shredded, and so quick is the action that the inner surface of the metal is compressed and densified against the outer metal. ”

“ It is a shrapnel with a detachable head filled with high explosive. When burst during flight it acts like an ordinary shrapnel, and the bullets fly forward and sweep the ground in front of it; at the same time the head, with its explosive burster, flies forward and acts as a small but efficient high-explosive shell. These projectiles have been introduced for howitzers and for anti-aircraft guns, and some of the nations with new [285] equipments, such as the Balkan States, have them for their field-guns. ”

“ The effect of these combinations will produce an explosive especially suitable for certain blast­ing purposes—for example, in crevice rock—and greatly superior either to gunpowder or gun-cotton in explosive force, and quite readily exploded, so that it may be fired and exploded by means of a match or electric spark in like manner as gunpowder or gun-cotton alone. ”

“ Again, as the projectile was simply a lump of oleaginous matter, it would have been blown by an explosive cartridge into thousands of fragments, each of them so small as to be worthless for incendiary purposes; for the efficacy of an incendiary depends to a great extent on its containing a large quantity of matter. ”

“ The fragmentation bombs differ from the demolition bombs in that they have thick metal walls and consequently smaller charges of explosive. They throw showers of fragments like those of high-explosive artillery shell. The demolition bombs contain, on the other hand, the maximum possible amount of explosive and produce destruction by the force of explosion. Fragmentation bombs always have instantaneous firing mechanisms, while demolition bombs are usually provided with delayed fuses, allowing them to penetrate the target before explosion. ”

“ If ignited with a red-hot rod, it burns but does not explode, unless it is enclosed. The burning, that is to say, is not sufficiently rapid to constitute an explosion.
On the other hand, if it be exploded by a detonator, by which is meant a small quantity of a very powerful explosive, such as fulminate of mercury, fired close [Pg 34] to it, it then goes off with a violence which leaves little to be desired.
It would be better still could we persuade a little more oxygen to enter into its composition, for as it is there is not quite enough to burn up the other matters completely. ”

“ If it was hoped that it would drop in a crowded spot and inflict the greatest amount of damage to human life and limb it would carry a bursting charge, shrapnel, and bits of iron, all of which on the impact of the missile upon the earth would be hurled in every direction to a radius exceeding forty yards. If damage to buildings, on the other hand, was desired, some high explosive such as picric acid would be used which would totally wreck any moderate-sized building upon which the shell might fall. ”

“ These containers may be special cylinders for cloud gas attacks, special bombs for Livens’ projectors and mortars, or artillery shell, and even aviation bombs. Some of the liquids which have a very low boiling point volatilize quickly upon exposure to air, and hence require only enough explosive to open the shell and allow the liquid to escape. Practically all solids have to be pulverized by a large amount of high explosive, or driven off as smoke by some heating mixture. ”

“ The writer was the first to dispel this folly, through the invention of Maximite, a high explosive which will stand not only the shock of being fired from heavy guns at high velocities, but which will also, without exploding, stand the far greater shock of penetrating the heaviest armorplate—armorplate as heavy as the projectile will stand to pass through without breaking up. ”

“ Any explosive whose detonation is very rapid is a high explosive, but the term has chiefly been applied to the nitro-explosives.
The effectiveness of an explosive depends upon the volume and temperature of the gases formed, and upon the rapidity of the explosion. In the high explosives the chemical transformation is very rapid, hence they exert a crushing of shattering effect. Gunpowder, on the other hand, is a low explosive, and produces a propelling or heaving effect. ”

“ Fortunately we are not so situated, but singularly enough what we have done in the field of high explosive projection has been accomplished by private enterprise, and we have attacked the problem at exactly the opposite point from which European nations have undertaken it. While they have assumed that the powder gun with its powerful and relatively irregular pressures was a necessity and have endeavored to modify the explosive to suit it, we have taken the explosive as we have found it, and have adapted the gun to the explosive. ”

“ It is evident that, for the purpose under contemplation, the destruction of the less substantial structural parts of aeroplanes, etc., if we are able to secure the proper and immediate expansion of the bullet on impact without the use of an explosive charge, every useful purpose will be served. The bullet energy, even reduced to about one-quarter of its initial value by 1,000 yards flight, is more than sufficient, if definitely expended in the impact, to destroy any strut or spar or other light constructional part, without any aid from an explosive charge. ”

“ But by the researches of Nobel, Professor Abel, and others, it has been discovered—and this is, perhaps, the most remarkable discovery in connection with explosives—that gun-cotton, nitro-glycerine, and other explosive bodies, are capable of producing explosions in a manner quite different from that which attends their ignition by heat. The violence of this kind of explosion is far greater than that due to ordinary ignition, for the action takes place with far greater rapidity throughout the mass, and is, indeed, practically instantaneous. ”

“ It will have become obvious from the preceding paragraphs that, according to the conditions under which an explosive is to be used, selection must be made of the most suitable. For example, the substances employed for propelling projectiles from guns must not have the violent rending power of certain others, which, by this very property, are most useful for blasting operations; and, again, although explosives of this last kind are inadmissible as projectile agents, they are of the kind best adapted for use in shells where it is the disruptive action that is required. ”

“ Dynamite is used mostly for commercial blasting purposes, such as blasting rock in the construction of railways, and so forth. [2] Military high explosives are mostly employed for submarine mines, warheads for torpedoes, and as bursting charges for high explosive projectiles.
A high explosive is consumed almost instantly by what is called a detonative wave ”

“ The time which has elapsed to reach this stage of the explosion depends on the bomb energy. If two explosions are compared, and the bigger one has a thousand times the explosive power of the smaller one, then the time needed to reach the extreme expansion of the fireball will be approximately ten times greater for the more violent event. In any case, a reasonably close observer has to use strongly absorbing glasses during this time if he is not to be blinded. For small bombs, the expansion of the fireball is too short to register. ”

“ Each of these guns is capable of hurling a projectile carrying five hundred pounds of the most powerful explosive known to man, and is able to destroy the strongest iron-clad. In the naval battle of Sinope in the Crimean War, a shell designed to explode on striking the object was used for the first time. When the high explosives, such as dynamite and gun-cotton, appeared, the idea suggested itself that they might be used in the shells with vastly greater effect than gunpowder, which had been employed. ”

“ The bomb, not being pointed, does not sink into the ground, and hence upon exploding exerts the full force of high explosive upon the surroundings, whether bombs, pill boxes, barbed wire or trenches, to say nothing of personnel. ”

“ If the explosive proves sufficiently insensitive to indicate that it will stand the impact or shock of penetrating armor plate, it is then tested to determine its explosive power. A forged steel armor-piercing shell is filled with the material and armed with a very powerful exploder, which is set off by electricity. The force of the explosive is shown by the number and character of the fragments. Small shells are burst for fragmentation in a steel-walled chamber; larger shells are buried in the sand and exploded, the fragments being recovered by sifting the sand. ”

“ From above the French, American and British airmen were dropping tons of explosives on the emplacements of the big guns and on the railway spurs that brought them to the firing points. It might seem an easy matter for an airship flying over a place to drop an explosive bomb on it and destroy it. But, on the contrary, it is very difficult.
The bombing plane must be constantly on the move, and it takes a pretty good eye to calculate the distance from a great height sufficiently well to make a direct hit.
But a certain percentage of the bombs find their mark, and they did in this case. ”

“ The explosion of the fulminate causes the detonation of the dry gun-cotton at the bottom of the priming tube, and this is taken up by the whole mass of the explosive with destructive effect. The danger of premature or accidental explosion by anything coming in contact with the projecting striker is obviated by several checks which prevent any chance blow driving the rod home against the fulminate charge. ”

“ For breaking up hard rock, blowing up strong masonry, and especially in demolitions where tamping is usually defective, this ratio does not hold; but the relative effect of the high explosive increases continually with the lack of tamping and the intensity of the local blow desired, until a point is reached at which the effect of gunpowder is almost imperceptible, while the high explosive does efficient work. This property of the high explosives renders them extremely valuable for 133 use in hasty demolitions, such as blowing up palisades or barriers, destroying guns, etc., etc. ”

“ If then we can fill the small cavity in the shell with an explosive which will not ignite prematurely, and yet will burst the shell properly after it has passed through the armor, the problem will be solved. Wet or paraffined gun-cotton can be made sluggish enough to satisfy the first condition; but at present the difficulty is to make it explode at all. The more sluggish the gun-cotton, the more powerful must be the fuse exploders to detonate it, and such exploders are themselves liable to premature ignition in passing through the armor. ”