This page has been validated.
198
THE EVOLUTION OF WORLDS
ones supposed, and we should expect a southern polar cap, larger at its maximum and still more so, relatively, at its minimum, than in the opposite hemisphere. Let us now look at the facts, for we have now a knowledge
| Mars | |||
| NORTH POLAR CAP. | SOUTH POLAR CAP. | ||
| At maximum full | extent of white | At maximum | white |
| At minimum | inner circle | At minimum | nothing |
of the Martian polar caps exceeding in some respects what we know of our own. The accompanying diagrams exhibit the state of things at a glance, the maximum and minimum of each cap being represented in a single picture and the two being placed side by side. It will be observed that the southern cap outdoes its antipodal counterpart at its maximum, showing that the longer, colder winter has its effect in snow or hoar-frost deposition. But, on the other hand, instead of excelling
