SCHIAPARELLIS LATEST VIEWS REGARDING MARS. 121 



the seas of Mars we see the color become darker when tlie sun approaches 

 their zeuith, and summer begins to rule in tbat region. 



All of the remainder of the planet, as far as the north pole, is occu- 

 pied bj' the mass of the continents, in which, save in a few areas of rel- 

 atively small extent, an orange color predominates, which sometimes 

 reaches a dark red tint, and in others descends to yellow and white. 

 The variety in this coloring is in part of meteorological origin, in part 

 it may depend on the diverse nature of the soil, but upon its real cause 

 it is not as yet possible to frame any very well grounded hypothesis. 

 Nevertheless, the cause of this predominance of the red and yellow 

 tuits upon the surface of ancient Pyrois is well known. ^ Some have 

 thought to attribute this coloring to the atmosphere of Mars, through 

 which the surface of the planet might be seen colored, as any terres- 

 trial object becomes red when seen through red glass. But many facts 

 are o.pposed to this idea, among others that the polar snows appear 

 always of the purest white, although the rays of light derived from 

 them traverse twice the atmosphere of Mars under great obliquity. 

 We must then conclude that the Arean continents appear red and 

 yellow because they are so in fact. 



Besides these dark and light regions, which we have described as 

 seas and continents, and of whose nature there is at present scarcely 

 left any room for doubt, some others exist, truly of small extent, of an 

 amphibious nature, which sometimes appear yellowish like the con- 

 tinents, and are sometimes clothed in brown (even black in certain 

 cases), and assume the appearance of seas, whilst in other cases their 

 color is intermediate in tint, and leaves us in doubt to which class of 

 regions they may belong. Thus all the islands scattered through the 

 Mare Australe and the Mare Erythrteum belong to this category 5 so 

 too the long peninsula called Deucalionis Kegio and Pyrrhfe Kegio, 

 and in the vicinity of the Mare Acidalium the regions designated by 

 the names of Baltia and Nerigos. The most natural idea, and the one 

 to which we should be led by analogy, is to suppose these regions to 

 represent huge swamjis, in which the variation in depth of the water 

 produces the diversity of colors. Yellow Avould predominate in those 

 parts where the depth of the liquid layer was reduced to little or 

 nothing, and brown, more or less dark, in those places where the water 

 was sufficiently deep to absorb more light and to render the bottom 

 more or less invisible. That the water of the sea, or any other deep 

 and transparent water, seen from above, api)ears more dark the greater 

 the depth of the liquid stratum, and that the land in comparison with 

 it appears bright under the solar illumination, is known and continued 

 by certain iihysical reasons. The traveler in the Alps often has occa- 

 sion to convince himself of it, seeing from the summits the deep lakes 



• Pyrois I take to be some terrestrial region, although I have not been able to Unci 

 any translation of the name. — Translator. 



