Though little more than half the earth's size, Mars has a significance in the public eye which places it first in importance among the planets. It is our nearest neighbor on the outer side of the earth's path around the Sun and, viewed through a telescope of good magnifying power, shows surface markings, suggestive of continents, mountains, valleys, oceans, seas and rivers, and all the varying phenomena which the mind associates with a world like unto our own. Indeed, it possesses so many features in common with the earth, that it is impossible to resist the conception of its being inhabitated. This, however, is not tantamount to saying that if there is a race of beings on Mars they are the same as we on Earth. By no means. Whatever atmosphere exists on Mars must be much thinner than ours and far too rare to sustain the life of a people with our limited lung capacity. A race with immense chests could live under such conditions, and folk with gills like fish could pass a comfortable existence in the rarefied air. Besides the tenuity of the atmosphere, there are other conditions which would cause life to be much different on Mars. Attraction and gravitation are altogether different. The force with which a substance is attracted to the surface of Mars is only a little more than one-third as strong as on the earth. For instance one hundred pounds on Earth would weigh only about thirty-eight pounds on Mars. A man who could jump five feet here could clear fifteen feet on Mars. Paradoxical as it may seem, the smaller a planet, in comparison with ours and consequently the less the pull of gravity at its centre, the greater is the probability that its inhabitants, if any, are giants when compared with us. Professor Lowell has pointed out that to place the Martians (if there are such beings) under the same conditions as those in which we exist, the average inhabitant must be considered to be three times as large and three times as heavy as the average human being; and the strength of the Martians must exceed ours to even a greater extent than the bulk and weight; for their muscles would be twenty-seven times more effective. In fact, one Martian could do the work of fifty or sixty men.