20 4 THE POPULAR SCIENCE MONTHLY. 



who weighs 150 pounds on the Earth, if transported to Jupiter, would 

 shake the ground with a ponderous tread of 45,000 pounds, or 22| 

 tons ! His own weight would at once crush him into a mere pulp. A 

 hickory-nut, falling from a bough, would crash through him like a 

 Minie-ball. Again, water would weigh fifteen times as much as quick- 

 silver. A moderate wave would shiver to atoms the strongest iron- 

 clad, a rivulet would quickly form canons miles deep, and ordinary 

 hailstones would destroy every living thing. If we suppose the exist- 

 ence of an atmosphere, even no more profound than our own, its weight 

 would be a third that of water, and its pressure 4,500 pounds to the 

 square inch sufficient to crush a rhinoceros or the boiler of a steam- 

 engine. In motion, as a moderate breeze, it would sweep away not 

 only every work of man, but the very hills and mountains. The same 

 condition, in less degree, may be predicated of the lesser of the giant 

 planets, and Jupiter is only selected as the most striking example. 



Putting aside the hundreds of known, and the thousands and millions 

 of unknown asteroids, as obviously unfit for life, let us next consider 

 the case of Mars. The relative mass of Mars being only about -^ that 

 of the Earth, it follows, as a necessary consequence of the laws of gravi- 

 tation, that our typical man would only weigh about 2^ pounds on the 

 surface of that planet. Individual locomotion would be wonderfully 

 facilitated, but its conditions would be reversed. The familiar dream 

 of flying by a mere upward movement of the limbs might easily be 

 realized in Mars, but an 80-ton locomotive would not propel a train of 

 empty cars, and mechanical work of all kinds would be practically im- 

 possible. Niagara Falls, in such a planet, with water approximating 

 the weight of air, would scarcely furnish power for a mill. A rifle- 

 ball might be caught in the hand without harm. It is obvious that, 

 with an atmosphere of the density of our own, animal and vegetable 

 life, and every artificial work, representing so many structures of gos- 

 samer, would disappear like magic at the first breeze. But no such 

 atmosphere as ours is possible with Mars. Even supposing it to equal 

 our own in altitude, its pressure would be only about one fourth of a 

 pound to the inch. Life is impossible in such an atmosphere, as is 

 shown by a far less tenuity at the summits of lofty mountains. But, 

 even if gravitation were not deficient, the distance of Mars from the 

 sun entitles him to considerably less than half our supply of light and 

 heat ; a disadvantage immensely aggravated by his very eccentric 

 orbit. Croll has shown how the shifting eccentricity of the earth's 

 orbit, by adding three weeks to the duration of winter, brought about 

 the glacial epochs, and covered nearly the whole earth with ice at 

 various eras. Conceive, then, the thermometer in the Martial torrid 

 regions touching 50, and that even under the hypothesis, rendered 

 impossible by the very laws of gravitation, of an atmosphere as dense 

 as our own ! Nothing can be more certain than that there is no liquid 

 in Mars, and no life. 



