High-angle fire with long shell.
Modern fortification dates by universal consent from 1885. The Germans
had begun experiments a year or two before this, with long shell
containing large charges of gun-cotton. But it was the experiments at
Fort Malmaison in France in 1886 that set the military world speculating
on the future of fortification. The fort was used as a target for 8-in.
shell of five calibres length containing large charges of melinite. The
reported effects of these made a tremendous sensation, and it was
thought at first that the days of permanent fortification were over.
Magazine casemates were destroyed by a single shell, and revetment walls
were overturned and practicable breaches made by two or three shells
falling behind them. It must be remembered, however, that the works were
not adapted to meet this kind of fire. The casemates had enough earth
over them to tamp the shell thoroughly, but not enough to prevent it
from coming into contact with the masonry, and the latter was not thick
enough to resist the explosion of the big charges. Other experiments
were made in the same direction in Germany, Holland, Belgium and
Austria. The Germans used shell containing from 60 to 130 lb. of high
explosive.
After the first alarm had subsided foreign engineers set about adapting
their works to meet the new projectiles. Revetments were enormously
strengthened, and designed so that their weight resisted overturning.
Concrete roofs were made from 6 to 10 ft. thick, and in many cases the
surface of the concrete was left bare so as to expose a hard surface to
the shell without any earth tamping. The idea of cupolas and shielded
guns gained ground, and is now practically accepted all over the
continent of Europe. In many cases the main armament, in some only the
safety armament (see below), is in cupolas in the forts.
[Illustration: From Plessix and Legrand's _Manuel complet de la
fortification_, by permission.