Chapter III: ELECTRICITY.--A New Electric Ballistic Target.--A target

for investigations of the velocity of projectiles, now in use at
the United States Military Academy, West Point, N.Y.--1
illustration.

Electric Erygmascope.--An electric lighting apparatus for
examining earth strata in bore holes for geologists' and
prospectors' use.--1 illustration

The Electro-Magnet.--By Prof. SILVANUS THOMPSON.--Continuation
of this exhaustive treatise, giving further details on special
points of construction.--1 illustrations