SCHIAPARELLl's LATEST VIEWS REGARDING MARS. 117 



is in the midst of a hu.iie dark sj)ot, wbicli with its branches occupies 

 nearly onethird of the whole surface of Mars, and is sn])posed to repre- 

 sent its principal ocean. Hence the analogy with our arctic and 

 antarctic snows may be said to be complete, and especially so with the 

 antarctic one. 



The mass of the northern snow cap of Mars is, on the other hand, 

 centered almost exactly upon its pole. It is located in a region of 

 yellow color, which we are accustomed to consider as representing the 

 continent of the planet. From this arises a singular phenomenon which 

 has no analogy upon the earth. At the melting of the snows accumu- 

 lated at that pole during the long night of ten months and more the 

 liquid mass produced in that operation is diffused around the circum- 

 ference of the snowy region, converting a large zone of surrounding 

 land into a temporary sea and filling all the lower regions. This pro- 

 duces a gigantic inundation, which has led some observers to suppose 

 the existence of another ocean in those parts, but which does not really 

 exist in that place, at least as a permanent sea. We see then (the last 

 opportunity was in 1884) the white spot of the snow surrounded by a 

 dark zone, which follows its perimeter in its progressive diminution, 

 upon a circumference ever more and more narrow. The outer part of 

 this zone branches out into dark lines, which occupy all the surround- 

 ing region, and seem to be distributary canals by which the liquid 

 mass may return to its natural position. This produces in these regions 

 very extensive lakes, such as that designated upon the map by the name 

 of Lacus Hyperboreus ; the neighboring interior sea called Mare Acida- 

 liuin becomes more black and more conspicuous. And it is to be 

 remembered as a very probable thing that the flowing of this melted 

 snow is the cause which determines principally the hydrographic state 

 of the planet and the variations that are periodically observed in its 

 aspect. Something similar would be seen upon the earth if one of our 

 poles came to be located suddenly in the center of Asia or of Africa. 

 As things stand at present, we may find a miniature image of these 

 conditions in the flooding that is observed in our streams at the melt- 

 ing of the Alpine snows. 



Travelers in the arctic regions have frequent occasion to observe how 

 the state of the polar ice at the beginning of the summer, and even at 

 the beginning of July, is always very unfavorable to their progress. 

 The best season for exploration is in the month of August, and Sep- 

 tember is the month in which the trouble from the ice is the least. 

 Thus in September our Alps are usually more practicable than at any 

 other season. And the reason for it is clear — the melting of the snow 

 reffuires time; a high temperature is not sufficient; it is necessary that 

 it should continue, and its efl'ecr, will be so much the greater, as it is 

 the more prolonged. Thus, if we could slow down the course of our 

 season so that each month should last sixty days instead of thirty, in 

 the summer, in such a lengthened condition, the melting of the ice 



