From the Earth to the Moon

ng 20,000 pounds being launched into space; they asked what cannon could ever transmit a sufficient velocity to such a mighty mass. Th

000 pounds. Now when a projectile is launched into space, what happens to it? It is acted upon by three independent forces: the resistance of the air, the attraction of the earth, and the force of impulsion with which it is endowed. Let us examine these three forces. The resistance of the air is of little importance. The atmosphere of the earth does not exceed forty miles. Now, with the given rapidity, the projectile will have traversed this in five seconds, and the period is too brief for the resistance of the medium to be regarded otherwise than as insignificant. Proceding, then, to the attraction

fficulty," brok

end on the length of the engine and the powder employed, the latter being limited only by the

nish the world by the dimensions we shall be obliged to adopt. It must evidently be, then, a gun of great range, since the length of t

major. "What is the

es the diameter of the shot, and its weight two hundred and

gh," cried J. T.

projectile nine feet in diameter, weighing 30,000 pounds, the gun would only have

ined Maston. "As w

is why I propose to quadruple that length,

ns; nevertheless, the proposition, actively sup

tone, "what thickne

six feet," rep

unting a mass like that upon

uperb idea, thou

ly surrounding it with a thick mass of masonry of stone and cement. The piece once cast, it must be bored with great precision, so as to preclud

said Elphinstone: "is

mous initial velocity; and you are well aware that a shot q

ejoined t

urned for a few minutes

eration the metal to be employed. Our cannon must be possessed of great tenacity, great har

"and as we shall have to employ an immense quanti

loy hitherto known, which consists of one hundred

resent case it would be too expensive, and very difficult to work. I think, then, that we ought to a

with you," repl

it is easy of manipulation, it is at once economical of money and of time. In addition, it is excellent as a material, and I well rememb

y brittle, though

orthy secretary to calculate the weight of a cast-iron gun wi

ome algebraical formulae with marvelous facility,

040 tons. And, at two cent

d and ten thousand seven

he general regarded Barb

I repeat what I said yesterday. Make yourse

committee separated, after having fixed the