122 THE PLANET MARS: IS IT INHABITED? 



regions. Mars, a much smaller planet, is four thousand two hun- 

 dred and fifteen miles in diameter, which, multiplied by its circum- 

 ference, thirteen thousand two hundred and forty-one miles, shows 

 its area to be nearly fifty-six millions of square miles, from which, 

 deducting an average of six and a half millions for North and 

 South snow-caps, we have forty-nine and a quarter millions of land 

 only, which is more than the entire land area of Europe, Asia, 

 Africa, and America combined. It will surprise many to know 

 that out of the entire land area of our Earth, viz., fifty-one milHons 

 of square miles, about twenty millions have not been explored at 

 all, estimated thus : — Africa, six and a half millions ; Arctic and 

 Antarctic regions, nine millions ; other parts, four and a half mil- 

 lions. As would appear from the extent of country covered by 

 lines, our Martian cousins may be far ahead of us in the work of 

 exploration. 



An important correction to our former beliefs lies in the dis- 

 covery that the large dark areas on Mars are not seas, but in all 

 probability the bottoms of ancient seas, which are flushed at 

 certain seasons by extensive freshets from the melting snows at 

 the North and South Poles. These waters, never apparently very 

 deep, disappear during summer and autumn, being either absorbed 

 by vegetation and the subsoil, or vapourised into the atmosphere. 

 We thus arrive at the pregnant inference, if Mr. Lowell's observa- 

 tions be confirmed, that a great scarcity of water exists upon Mars, 

 at least upon the surface, and as scarce there as it is plentiful with 

 us. Referring again to the strange periodical disappearance of 

 the dark areas, also the various changes in colour, recent observa- 

 tions not only confirm these variations, but add similar changes in 

 colour and visibility of the spots. Some hidden unknown cause 

 was here at work. That large markings should come and go in 

 this way, showed changes to exist on a scale involving a large 

 portion of the planetary surface. In a correct interpretation of 

 these changes evidently lay the key to the unlocking of the mystery 

 of Mars. The exhaustive scrutiny of astronomers during the past 

 forty years, culminating in those of Schiaparelli and the Arizona 

 observers, may turn out to have brought us within measurable 

 distance of the true solution. 



Geology tells us that our oceans are gradually filling up with 



