addition to the dynamite gun projectiles (see TORPEDOES) there have been numerous experiments made to devise a method for the safe projection of high explosives. In 1887 experiments were made at Sandy Hook with steel shell of service pattern. but provided with a large base opening for convenience of loading ; the weight of each, including the bursting charge of 2.3 lbs. of dynamite, was about 122 lbs. The weight of powder charge was 23 lbs. The Graydon method of charging shell consists in subdividing the bursting charge into small pellets, each enclosed in a separate envelope, which is treated with paraffine. The interior of the shell is carefully lined with asbestos. The fuze is com posed of a funnel-shaped vessel of sheet metal, having its large end in contact with or close to the front wall of the projectile, while its rear end sits over the fuze proper, a cylindrical tube filled with powder and armed in front with a percussion cap. Seven rounds were fired at a section of a wrought-iron turret, 14 in. in thickness, and made up of two 7-in. plates ; each of these was divided horizontally into two sections, so disposed as to break joints. The shell were successfully fired from the gun, and serious damage was inflicted on the target ; especially was this the case in the third round, when penetration and disruptive effect on the target were combined. This system has since undergone a series of trials in England and France, where, on account of there being neither special gun nor special projectile required, it has attracted considerable attention.
The Smolianinoff shell, charged with high explosive, was fired from a 100-pounder Parrott rifle at the Sandy Hook proving grounds in November, 1887. The weight of empty shell in the first two rounds was 89 lbs.. and the weight of explosive was lbs.; in the last round the shell weighed 82 lbs., the explosive lbs. The explosive consists of 80 per cent. of nitro-glycerine, and it is claimed that it is insensible to shock, either in the gun or against a target of earth or stone, and that a detonating fuze is required to explode it. The weakness of the cast-iron shell used in the three rounds that were fired, and also the shape of the head, which was adapted to a nose-fuze, precluded any possibility of penetrating the target, which was like the one above described. The firing was successful in the respect that no damage
was done to the gun.
The Snyder explosive consisted of 94 per cent. nitro-glycerine, and 6 per cent. of a pound of collodion, gun-cotton, camphor, and ether ; it is exploded by mere percussion against any hard and solid body, and it seems to be wholly within the power of the manipu lator to prevent premature explosions. The gun employed in the experiments, that took place under direction of the Turkish war department, was a 6-in. rifled field-piece. The target, erected at a distance of 220 yards, was composed of twelve 1-in. steel plates, welded together, and backed by oak beams; the charge of explosive was 10 lbs. Ten shots were fired without accident of any kind, and without damage to the gun, the target being corn. pletely destroyed by one of the shots.
In 1883, in Germany, a patent was obtained for the construction of a shell to be charged with high explosive, but nothing in the way of experiments was done with the projectile. which was of special construction, and in 1885 a patent was secured for a new process of loading, which could be applied to shell of service pattern. The wet gun-cotton used in this is in the form of prismatic grains, made by cutting up the ordinary compressed disks, and to the charge of wet are added about 200 grams of dry cotton. Space being reserved for the fuze and detonator, melted paraffine is poured over the charge, filling in all its inter stices, and, as it cools, forms the charge into a solid mass. Over 200 shell have been fired from an 8.S-cmt. gun without accident, and with complete explosion. Charges of 16 kilograms have been successfully fired from the 15-cmt., and the experiments have since extended to the 28-cmt. mortar. In March, 1888, a 98-kilogram projectile, loaded with gun-cotton and 22 kilograms of powder, was fired from a 21-cmt. Krupp gun. The shell perforated a 12-cmt. compound plate, its 60 cots. of oak backing, and only burst when it entered an earthen wall at the rear of the target. (See ARMOR ; GUN, PNEUMATIC ; ORDNANCE, and TORPEDOES.) Projectiles, Dynamite : see Torpedo.
Propellor : see Engines, Marine.
Pug Mill : see Clay-working ?Machinery.