The War Terror

Without a word, Kennedy seemed to take in the scant furniture of the laboratory at a glance and a quick step or two brought him before a steel filing cabinet. One drawer, which had not been closed as tightly as the rest, projected a bit. On its face was a little typewritten card bearing the inscription: "E-M GUN."


He pulled the drawer open and glanced over the data in it.


"Just what is an electro-magnetic gun?" I asked, interpreting the initials on the drawer.


"Well," he explained as he turned over the notes and sketches, "the primary principle involved in the construction of such a gun consists in impelling the projectile by the magnetic action of a solenoid, the sectional coils or helices of which are supplied with current through devices actuated by the projectile itself. In other words, the sections of helices of the solenoid produce an accelerated motion of the projectile by acting successively on it, after a principle involved in the construction of electro-magnetic rock drills and dispatch tubes.


"All projectiles used in this gun of Fortescue's evidently must have magnetic properties and projectiles of iron or containing large portions of iron are necessary. You see, many coils are wound around the barrel of the gun. As the projectile starts it does so under the attraction of those coils ahead which the current makes temporary magnets. It automatically cuts off the current from those coils that it passes, allowing those further on only to attract it, and preventing those behind from pulling it back."