328 ANNUAL OF SCIENTIFIC DISCOVERT. 



toward us. The improved instruments of the last generation have 

 therefore been employed as yet successfully only on the southern 

 hemisphere. 



There is every reason, then, to think that human life on Mars might 

 be very much like human life on the Earth. The light cannot be so 

 bright, but the organs of sight may be so much more susceptible as to 

 make the vision quite as good. The heat is probably less, as the polar 

 snows certainly extend further ; but by no means less in proportion to 

 the lessened power of the solar rays. The density of the rocks and 

 geological strata is very nearly the same, and the peculiar red color of 

 the planet has sometimes been ascribed to a preponderance of red 

 sandstone. 



Additional Observations on Mars. An account of some recent 

 carefully conducted observations on Mars have also been laid before 

 the Eoyal Society, by Professor J. Phillips, of Oxford. He states that 

 the position of the planet in the autumn of 18G2 was so favorable 

 " that the entire circle of snow around the South Pole could be dis- 

 tinctly seen, and with such a well-defined edge as to have led to the 

 conclusion that it terminates in a cliff. The equatorial region is occu- 

 pied by a broad greenish belt fringed with deep bays and inlets, which 

 may perhaps be water. In one place it is relieved by an island which 

 exhibits the same ruddy color as the hemispheres on each side of the 

 central belt. 



During the past year, Mr. Nasmyth, of England, has also announced 

 that his observations on Mars tend to confirm the existence of an 

 island in the supposed sea of that planet. 



RESEARCHES ON THE MOON. 



During the last few years the surface of the Moon has been mapped 

 and measured by several observers, and its features laid down with as 

 much exactness as if the subject of delineation was some mountainous 

 region of our own planet. The moon's surface presents a wondrous 

 scene of lofty isolated heights, craters of enormous volcanoes, ramparts, 

 and broad plains that look like the beds of former seas, and present a 

 remarkable contrast to the rugged character of the rest of the surface- 

 That what we look upon are really mountains and mountainous ranges 

 is sufficiently evident from the fact that the shadows they cast have 

 the exact proportion as to length which they ought to have from the 

 inclination of the sun's rays to their position on the moon's surface. 



The convex outline of the moon, as turned toward the sun, is always 

 circular, and nearly smooth ; but the opposite border of the enlightened 

 part, instead of being an exact and sharply defined ellipse, is always 

 observed to be extremely rugged, and indented with deep recesses 

 and prominent points. The mountains near the border cast long black 

 shadows, as they should evidently do, inasmuch as the sun is rising or 

 setting to those parts of the moon. But as the enlightened edge grad- 

 ually advances beyond them, or, in other words, as the sun to them 

 gains altitude, their shadows shorten ; and at the full moon, when all 

 the light falls in our line of sight, no shadows are seen. By micromet- 

 rical measurement of the length of the shadows, the heights of the 

 more conspicuous mountains can be calculated. Before the year 1850, 

 the heights of no fewer than one thousand and ninety-five lunar moun- 



