Having now explained how the knowledge came to be arrived at that the aforementioned compound of highest grade nitro-glycerine and highest grade gun-cotton would constitute the best basis for a smokeless powder, I will now mention a few of the other conditions necessary to success with its use, without assuming that smokeless powder has yet passed its experimental stage, and is beyond further improvement. Nevertheless, such is the compound which has come to stay as the basis of all smokeless powders; and any smokeless powder, if a successful one, may be counted upon as being made of this compound of gun-cotton and nitro-glycerine, or of a colloid of gun-cotton, either alone or combined with diluents, oxygen-bearing salts, or inert matter. The fact that smokeless powder may still be said to be in somewhat of an experimental stage is not to admit that it is not a success. Firearms, cartridge cases, and projectiles are also still in an experimental stage, for they are constantly being improved; yet their use has been a great success for a good many years.

The question of success of a smokeless powder does not rest alone with the powder itself. The gun, the cartridge case, primer, and bullet have been as much the subjects of experiments in adapting them to the use of smokeless powder as has the smokeless powder in being adapted to them. To impart a velocity of 2,000 feet per second to a rifle ball, with corresponding long range and accuracy of flight, has been a question as much of improvement in rifles and projectiles as in the powder. To give a velocity of 2,000 feet per second to a bullet, requires a pressure of at least 15 English tons in the chamber of a gun. This would be a dangerous pressure in an old-fashioned shoulder arm; while a bullet made only of lead would strip on striking the rifling and pass right through the barrel of the gun without taking any rotary motion whatever. It might at first seem that the powder is the only thing to be considered; but high ballistics can only be obtained when everything else is adapted to its use.

The projectile, the cartridge case, the fulminating cap, and the gun have had to be all built up together, and a very large amount of experimenting has been necessary to determine what would constitute the best projectile, best cartridge case, best fulminating cap, and what should be the character of the rifling and the quality and temper of the steel of the gun barrel.

It has been necessary first to conduct experiments to test the smokeless powders for velocities and pressures, and then with the powders test various kinds of projectiles and guns. In order to obtain the high ballistics which have been secured, it has been found necessary to cover the bullet with something harder than lead and to rifle the gun in a special manner.

The French, who were the first to definitely adopt smokeless powder, were the first also to make a rifle, projectile, cartridge case and primer suited to its use.

To obtain long range with a small long bullet such as is now used, it should rotate at a very high speed. It is well known to artillerists that a projectile of four or more calibers in length has to be rotated at a much higher speed than one of half that length, in order to keep the projectile stiff in the air, and to prevent it from ending over in its flight. To communicate this very high rotary movement to the bullet in the instant of time during which it is passing through the barrel, the rifling of the gun has to exert an enormous torsion on the bullet. Lead, no matter how hardened, is not sufficiently strong, as it will not only strip and pass straight through the gun without taking any rotary movement whatever, but under such very high pressures it behaves like wax, and is thrown from the gun in a distorted mass.

The French cover their bullets with German silver, a substance made of nickel, zinc and copper; and in order to put as little strain upon the rifling and projectile as possible, the rifling of the gun is made with an increasing twist, and has no sharp edges. The French rifle is made very strong at the breech and is of tempered steel throughout. In this way the French have made smokeless powder a success--a smokeless powder made substantially of a character such as I have herein described. With smokeless powder, the French rifle imparts a muzzle velocity of 2,000 feet per second to the bullet, with a range of about 2,400 meters.

If smokeless powder be divided into sufficiently small grains to be ignited by an ordinary fulminating cap, it would burn too quickly, thereby causing the pressure to mount too high, and without giving the desired velocity. Consequently very large and strong fulminating caps have to be employed. Smokeless powder is not ignited in the same manner as black powder. Something besides ignition is necessary. Black powder simply requires to be set on fire; while a smokeless powder, on the contrary, not only requires that it be set on fire, but that a certain degree of pressure be set up inside of the cartridge case. For instance, if a primer of a certain size should be found to operate perfectly well, giving prompt ignition in the cartridge case of a rifle of small caliber, it would be found that the same primer would not ignite a charge of the same powder if loaded into a gun of one inch caliber. In the latter case a few grains only lying near the primer would be ignited, and these would soon become extinguished by sudden release of pressure bringing about a cooling effect due to expansion of the gases.

In small cartridges a large fulminating cap is all that is required, but in large cartridges it is necessary to resort to additional means of ignition.

In France, where experiments were conducted with a 37 millimeter Maxim gun, it was found to be impracticable to use a fulminating cap sufficiently large to ignite the powder and cause it to burn. Therefore, a small ignition charge of black powder was employed, it being put in a capsule or bag and placed next the primer. On firing at the rate of 300 rounds per minute, the black powder, though small in quantity, produced a cloud of smoke through which it was quite impossible to see. The inventor of the gun then prepared for the French some wafers of pyroxyline canvas, which were placed next to the primer, securing thereby prompt ignition without the production of any smoke.

Smokeless powder, made as I have described, cannot be detonated by a fulminating cap of any size or by any means whatever. A large charge of fulminate of mercury placed inside the cartridge case next the primer will not detonate the powder, it serving only to ignite it and cause it to explode. But even this would not cause the powder to explode except it be confined behind a projectile, that sufficient pressure may be run up to make it burn in its own gases.

Some curious experiments with smokeless powder may be tried with a shot gun. If the fulminating cap be large, the powder fine, the wads numerous and hard and the charge of shot heavy, all being well rammed down, and the paper case well spun over the last pasteboard wad, a charge of smokeless powder about equal in weight to one-half of what would be employed of black powder would give about the same results as black powder. But if the charge of shot be omitted, the primer will only ignite the powder, and there will be set up sufficient pressure merely to throw the wads about half way up the barrel of the gun, when the powder will go out. Now if this same charge of powder be collected and reloaded into a new cartridge case and well confined behind wads and a charge of shot, as above explained, it will all burn, giving the same results as black powder.

Attempts have been made to use this powder in pistols and revolvers, but here it has proved a failure, as the pressure is not great enough to cause the powder to be consumed, unless it be in the form of very fine grains or dust, in which case the pressure mounts too high. However, this might be overcome to a degree by making the powder porous. The chemical conditions of the powder might be the same, but the physical conditions must be different. A powder suitable for shot guns and pistols would not be suitable for rifles.

One not familiar with the characteristics of smokeless powder would be almost certain to fail in his first attempt to fire it. Many persons have been convinced by their first experiments that this powder would not burn at all in a gun, any more than so much sand.

Smokeless powder is consumed with a rapidity which accords with the conditions of its confinement. Therefore, the bullets which have been experimented with by different governments have been the cause of much of the varying pressures attributed to the smokeless powders.

The Austrians use the Mannlicher steel jacketed bullet. The steel casing or jacket is first tinned on the inside and then the lead is cast in, thus melting the tin and adhering firmly to the jacket. This projectile sets up enormous friction in the barrel of the gun when used with smokeless powder; as the smokeless powder leaves the gun barrel perfectly clean and the two steel surfaces being in absolute contact cause tremendous friction; and as the coefficient of friction varies with every shot, the pressure in the gun constantly varies greatly.

The German silver covered bullet used by the French has the disadvantage that when firing rapidly the chamber of the barrel becomes nickel plated and great friction is caused, mounting up the pressures and causing the muzzle velocities to fall off.

The Austrians, in order to prevent their steel cased bullets from rusting and to lessen the friction in the barrel of the gun, cover them with a heavy lubricant, which gives the cartridges an unsightly appearance and causes them to gather dust and sand. The French employ a lubricant at the base of the projectile, with a small copper disk between the same and the powder.

Col. A.R. Buffington, commander of the National Armory at Springfield, Mass., has made a steel covered projectile which he prevents from rusting by blackening by a niter process. Several grooves are pressed in the base of the bullet which carry a lubricant, and when the bullet is inserted in the cartridge case the grooves are covered by it. Furthermore, these grooves prevent the lead filling from bursting through the steel casing, leaving the latter in the barrel, as often occurs with the Austrian and French projectiles when using smokeless powder.

A new projectile has lately come out, the invention of Captain Edward Palliser, of the British army. This bullet consists of a jacket made of very soft Swedish wrought iron, coated with zinc and filled with lead, the lead being pressed into this jacket. The bullet is corrugated at its base, after the manner of the one made by Colonel Buffington. This projectile has been experimented with very extensively by the British government, and at the works of the Maxim-Nordenfelt Guns and Ammunition Company, in England. The zinc coating of the bullet is too soft to stick to the barrel of the gun, and also in a measure acts as a lubricant. This projectile has given better results than any other that has been experimented with. The great velocities and the most uniform pressures by the use of smokeless powder have been attained with this Palliser bullet.