used in modern warfare are called after their
inventors. The _Gatling gun_ is not much talked of to-day, but it was
a famous gun in its time, and took its name from the American
inventor, Richard Jordan Gatling, who lived in the early nineteenth
century, and devoted his life to inventions. Some were peaceable
inventions, like machines for sowing cotton and rice; but he is best
remembered by the great gun to which he gave his name.

Another famous gun of which we have heard a great deal in the Great
War is the _Maxim gun_, which again took its name from its inventor,
Sir Hiram Maxim. The _shrapnel_, of which also so much was heard in
the Great War, the terrible shells which burst a certain time after
leaving the gun without striking against anything, took its name from
its inventor. The chief peculiarity of shrapnel is that the bullets
fall from above in a shower from the shell as it bursts in the air.

But there are many other names which we should not easily guess to
come from the names of inventors. People talk of a macadamized road
without knowing that these roads are so called because they are made
in the way invented by John M'Adam, who lived from 1756 to 1836. The
name _macadam_ is often used now to denote the material used in making
roads. Sometimes this material is of a sort which John M'Adam would
not have approved of at all, for he did not believe in pouring a fluid
material over the stones, or in the heavy rollers which are now often
used in making new roads.

Another useful article, the homely _mackintosh_, takes its name from
that of another Scotsman, Charles Macintosh, who lived at the same
time as M'Adam. It was he who first, in 1823, finished the invention
of a waterproof cloth.

In the eighteenth and nineteenth centuries many great discoveries were
made in science, and many names of discoverers and inventors have been
preserved in scientific words. _Galvanism_, one branch of electricity,
took its name from Luigi Galvani, an Italian professor, who made great
discoveries about electricity in the bodies of animals. Every one has
heard of a galvanic battery, but not everybody knows how it got its
name.

_Mesmerism_, or the science by which the human mind is influenced by
suggestions from itself or another mind, took its name from Friedrich
Anton Mesmer, who first made great discoveries about animal magnetism.

Another famous discoverer of the powers of electricity, and one who is
still a young man,