Page:The evolution of worlds - Lowell.djvu/265

Rh differs from those of Mercury and Venus in that the body to which the regard is paid is not also the dispenser of light and warmth. In consequence, though the side of the Moon with which we are presented remains always

the same, we do not always see it; the light creeping over it with the progress of the lunation, from new to full. On this account the worst that happens to our Moon in its old age is that its day becomes its month. Our Moon is not peculiar in having its day and its month the same. On the contrary, it is now the rule with satellites thus to protract their days. So far as we can observe, all the large satellites of Jupiter turn the same face to him; those of Saturn pay him a like regard; while about those of Uranus and Neptune we are too far off to tell. Their direct respect for their primary, with only secondary recognition of the Sun, keeps them from the full consequences of their fatal