"I must provide against this danger. If I do not, there is a chance that we shall arrive at Mars with the ships half empty and the crews floating helplessly around us."
Mr. Edison's way of guarding against the danger was by contriving a little apparatus, modeled after that which was the governing force of the electrical ships themselves, and which, being enclosed in the air-tight suits, enabled their wearers to manipulate the electrical charge upon them in such a way that they could make excursions from the cars into open space like steam launches from a ship, going and returning at their will.
These little machines being rapidly manufactured, for Mr. Edison had a miniature laboratory aboard, were distributed about the squadron, and henceforth we had the pleasure of paying and receiving visits among the various members of the fleet.
But to return from this digression to our experience of the asteroid. The latter being a body of some mass was, of course, able to impart to us a measurable degree of weight. Being five miles in diameter, on the assumption that its mean density was the same as that of the earth, the weight of bodies on its surface should have borne the same ratio to their weight upon the earth that the radius of the asteroid bore to the radius of the earth; in other words, as 1 to 1,600.
Having made this mental calculation, I knew that my weight, being 150 pounds on the earth, should on this asteroid be an ounce and a half.
Curious to see whether fact would bear out theory, I had myself weighed with a spring balance. Mr. Edison, Lord Kelvin and the other distinguished scientists stood by watching the operation with great interest.
To our complete surprise, my weight instead of coming out an ounce and a half, as it should have done, on the supposition that the mean density of the asteroid resembled that of the earth—a very liberal supposition on the side of the asteroid, by the way—actually came out five ounces and a quarter!
"What in the world makes me so heavy?" I asked.
"Yes, indeed, what an elephant you have become," said Mr. Edison.
Lord Kelvin screwed his eyeglass in his eye, and carefully inspected the balance.