Year: 1878

Probably the most convenient assump- tion we can make, says Prof. Proctor, is that there may be creatures in general respect like ourselves on these moons of Mars. but that owing to the extreme rarity of the atmosphere their vital energy is so far reduced that they are not more active than we are, despite the feeble action of gravity in their world. The air must be exceedingly rare, most certainly, even if the quantity is propor- toned to the volumes of these moons. On this assumption the quantity of air is less than the quantity of terrestrial air, as one is less than 400 times 400 times 400-that is, it amounts only to 1-64, ,0OO,- 900 part of the terrestrial air.

 Being spread over surface which IS but 1-16O,OOO of the earth's it follows that the quantity of air above each square mile of surface is 1-4O0 part only of the quantity over each square mile of our earths surface. This would be little enough, in all conscience; but this IS not all. For the action of gravity being, according to our assumption, only 1-60O of terrestrial gravity, it follows that the atmospheric pressure, and therefore density, is further reduced in this degree, giving finally density equal only to 1-240,000 of the density of our own air.

 Now, at height of seven miles, where the atmospheric pressure IS reduced to one-fourth that at the sea level, men of ordinary constitution would perish in few minutes, if not instantly. In Cox wells ascent to nearly that height, Glaisher tainted, and Coxwell only just had strength left to pull the valve string with his teeth Chis hands being already powerless). Yet, atithe height of seven miles, the density of the air is 6O,0O0 times greater than that which, according to our very reasonable assumption, pre- vails at the surface of the Martian moons.

 We can very well believe, then, that in whatever way the inhabitants of these moons may be adapted, corporeally and constitutionally, for existence in their small homes, the rarity of the air there must tend to reduce their vital energy. So that we may well imagine that, in- stead of being able to leap to height of half mile or over distance of two or three miles, they are not more active than we on earth with 600 times greater weight but far more effective respira- tion. We might, perhaps, go even fur ther than this, and assume that, in order to give to the inhabitants of these moons locomotive powers proportioned in the same way to their own dimensions as ours are, they must be supposed very much smaller than we are.

 We might imagine them in an atmos- phere so exceedingly attenuated that creatures which could have vitality enough to move freely about must be no larger than flies or ants, and must have also some such provision as insects have for more effective respiration. In thls way we might find in the Martian moons miniature of our own earth; not only in the proportions of these worlds them selves, but also in the creatures living upon them. But 1t would not be very interesting to consider mere miniatures of our earth, such as the moons of Mars would thus come to be regarded Indeed in that case little more could be said than that all the relations presented by this earth were, or might be, represented in the Martian moons, but on a greatly reduced scale.