rewed in, but some of the
German shell are made in two halves which screw together. The Italians
were the first in this new field of investigation, but the Germans
soon followed, and after trying various materials were at length
reasonably successful with gun-cotton soaked in paraffin. Their 8.4
inch mortar shells of 5 calibers contain 42 pounds; those of 6
calibers contain 57 pounds; and the 11.2 inch mortar shells of 5
calibers contain 110 pounds.

The projectile velocity used with the mortars is about 800 f.s. The
effect of these shells against ordinary masonry and earth
fortifications is very great. The charge of forty-two pounds has
broken through a masonry vault of three feet four inches thick,
covered with two feet eight inches of cement and with three to five
feet of earth over all. The shell containing fifty-seven pounds, at a
range of two and one-half miles, broke through a similar vault covered
with ten feet of earth; but with seventeen feet of earth the vault
resisted. In 1883, experiments at Kummersdorf showed that a shell
containing the fifty-seven pound charge would excavate in sand a
crater sixteen feet in diameter and eight feet deep, with a capacity
of twenty-two cubic yards. The Italians have had similar experiences;
but it is notable that in both Germany and Italy several guns and
mortars have burst. The velocity in the guns is not believed to exceed
1,200 to 1,300 f.s., and it is not thought that the quantity of
gun-cotton is as great in the gun shells as in the mortars. I have
lately been informed on good authority that the use of gun-cotton
shells has been abandoned in the German navy as too dangerous.

The French, in their investigations in this field, found gun-cotton
too inconvenient, and decided upon melenite. This substance has
probably attracted more attention in the military world than all
others combined, on account of the fabulous qualities that have been
ascribed to it. Its composition was for a long time entirely a secret;
but it is now thought to consist principally of picric acid, which is
formed by the action of nitric acid upon phenol or phenyillic alcohol,
a constituent of coal tar. The actual nature of melenite is not
positively known, as the French government, after buying it from the
inventor, Turpin, are said to have added other articles and improved
it. This is probable, since French experiments in firing against a
partially armored vessel, the Bellequense, developed an enor