122 SCHIArARELLl's LATEST VIEWS REGARDING MARS. 



with wliich the region is strewn extending under his feet as black as 

 ink, whilst in contrast with them even the blackest rocks illuuiined by 

 the sunlight appeared brilliant. ' 



Not without reason, then, have we hitherto attributed to the dark 

 spots of Mars the part of seas, and that of continents to the reddish 

 areas which occupy nearly two-thirds of all the planet, and we shall 

 find later other reasons which confirm this method of reasoning. The 

 continents form in the northern hemisphere a nearly continuous mass, 

 the only important exception being the great lake called the Mare 

 Acidalium, of which the extent may vary according to the time, and 

 which is connected in some way with the inundations which we have 

 said were produced by the melting of the snow surrounding the north 

 pole. To the system of the Mare Acidalium undoubtedly belong the 

 temporary lake called Lacus Hyperboreus and the Lacus i^iliacus. 

 This last is ordinarily separated from the Mare Acidalium by means of 

 an isthmus or regular dam, of which the continuity was only seen to 

 be broken once for a short time in 1888. Other smaller dark spots are 

 found here and there in the continental area which we may designate 

 as lakes, but they are certainly not permanent lakes like ours, but are 

 variable in appearance and size according to the seasons, to the point 

 of wholly disappearing under certain circumstances. Ismenius Lacus, 

 Lunic Lacus, Trivium Charoiitis, and Propontis are the most conspicu- 

 ous and durable ones. There are also smaller ones, such as Lacus 

 Moeris and Fons Juventoe, which at their maximum size do not exceed 

 100 to 150 kilometers (GO to 90 miles) in diameter, and are among the 

 most difficult objects upon tbe planet. 



All the vast extent of the continents is furrowed upon every side by 

 a network of numerous lines or fine stripes of a more or less pro- 

 nounced dark color, whose aspect is very variable. These traverse the 

 planet for long distances in regular lines that do not at all resemble 

 the winding courses of our streams. Some of the shorter ones do not 

 reach 500 kilometers (300 miles), others, on the other hand, extend for 

 many thousands, occupying a quarter or sometimes even a third of a 

 circumference of the planet. Some of these are very easy to see, 

 especially that one which is near the extreme left-hand limit of our 

 map, and is designated by the name of Kilosyrtis. Others in turn are 

 extremely difficult, and resemble the finest thread of spider's web 

 drawn across the disk. They are subject also to great variations in 

 their breadth, which may reach 200 or even 300 kilometers (120 to 

 180 miles) for the Nilosyrtis, whilst some are scarcely 30 kilometers (18 

 miles) broad. 



'This observation of the dark color which deep water exhibits when scon from 

 above is fonnd already noted by the first author of antique memory, for in the 

 Iliad (verses 770-771 of Book V) it is described how "the sentinel from the hiffh 

 sentry box extends his glance over the wine-colored sea, olvoTra n6vTov." In the 

 version of Monti the adjective indicating the color is lost. 



