I. "A magnetic gun would have several advantages. For instance, the currents can be sent through the solenoids in turn as quickly as we desire by means of a commutator in a convenient spot, for instance, at the butt end of the gun, so as to follow up the bullet with ease, and give it a planetary flight. By a proper adjustment of the solenoids and currents, this could be done so gradually as to prevent a starting shock to the occupants of the car. The velocity attained by the car would, of course, depend on the number and power of the solenoids. If, for example, each solenoid communicated to the car a velocity of nine yards per second, a thousand solenoids, each magnetically stronger than another in going from breech to muzzle, would be required to give a final velocity of five miles a second. In such a case, the length of the barrel would be at least 1,000 yards. Economy and safety would determine the best proportions for the gun, but we are now considering the feasibility of the project, not its cost. With regard to position and supports, the gun might be constructed along the slope of a hill or mound steep enough to give it the angle or elevation due to the aim. As the barrel would not have to resist an explosive force, it should not be difficult to make, and the inside could be lubricated to diminish the friction of the projectile in passing through it. Moreover, it is conceivable that the car need never touch the sides, for by a proper adjustment of the magnetism of the solenoids we might suspend it in mid-air like Mahomet's coffin, and make it glide along the magnetic axis of the tube."