THE PLANET MARS.

243

We must confess that we can give no satisfactory answerto such a query. Some who have thought upon this subjecthave suggested, that a peculiar and prevailing tinge of thevegetation upon the surface of Mars may produce its ruddyhue. Others, that it may be due to a large amount of redsandstone among its rocks, or of red earth in its soil. But noexplanation yet given really meets the difficulties of the case.

The inclination of the equator of Mars to the plane of itsorbit round the Sun (a matter of some doubt) has untilrecently been considered to be about 27|°. If so, the pecu-liarities of its seasons would not be very different from thoseof the Earth , with the exception that they would be slightlyintensified ; its arctic circles extending only some four degreesfurther from the poles (or rather less), and its tropics the samedistance further from the equator, than our own limit of 23| 0 .*At any rate, so far as the question of the habitability ofMars is concerned, we may say :—Its day is only a littlelonger than our own : its surface is varied by land and sea,by snow-clad mountain and arctic ice: its temperate andtropical zones are not very different in extent from those ofthe Earth . But, at the same time (as may be seen fromMr. Green’s chart), the proportion of land compared with thatof water is probably much greater ; so that there is about anequal extent of each, instead of one part of land to three partsof water, as upon the Earth . The chart also indicates thatthe water frequently winds amongst the land in long inlets,and that it may be in general possible to journey the greaterpart of the distance between any two given localities by water.fOn the other hand, the year of Mars is very much longerthan our own. Moreover, as a consequence of the ovalness ofits orbit, the number of days in its successive seasons mustgreatly vary. This is the case to such an extent, that in the

* We understand that Professor Schiaparelli has recently deduced aninclination of rather less than 25°, which would cause the climatic zonesto correspond almost exactly with those of the Earth .

t Some modifications and additions must be admitted into the abovestatement, if the existence of Schiaparelli's canals be confirmed, and ifit be allowed that they are formed by water.