"May 8. The same reasons assigned in our last, why very light garments only were needed for the bodily comfort and happiness of the people of Mars apply with equal propriety, force, and truth, to the subject of their habitations. "Your rains are produced by vapors, mists, and emanations from your oceans, rivers, lakes, etc., which by virtue of solar attraction or a reversal of the law of gravitation the vapors, mists, etc., are drawn upward in space until a certain density is reached, differing in altitudes of height, when they become congealed by the force of the cold attenuated atmosphere there into small particles called rain drops, and these are carried along by the undercurrents of uncongealed clouds until a certain electro-magnetic condition is reached, when the clouds begin to empty and rid themselves of their burdened contents. "Now we have informed you of the progress the water of Mars has made in being dispossessed of its gross and weighty elements; hence there are none of these to ascend and to commingle in the formation of rain drops; hence none but the purer and refined elements of the water are exhaled and drawn upward, and consequently none but the pure and refined descend. These are in themselves comparatively light and of greatly diminished gravity, and therefore mild and pleasant in their effect. Especially does this become true as a resulting necessity, from the fact that there are no fierce winds or storms or cold temperature in the surrounding atmospheric belts or zones. The rains on Mars are more like your gentle dews of early autumn than your rains and showers. You at once take in the situation from this and preceding statements of facts that crude material structures are not necessary, even if the material for their construction could be found, and we have seen that such is not the case, for all things, including the material in detail out of which edifices are constructed, have progressed beyond and above their crude grossness.