Arizona silver belt., 1895-05-18
THE WEATHER ON MARS.
Visible Evidences of a Warm
 Spoil on the Planot.
An Extensive Thaw Observed Which tn- dIcatcd a summer Season m the Southern Hemisphere of Our
 Neighhoring World,

Among the most interesting ubserya- tions of Mars during tho recent opposi- ton were those relating to the gradual disappearance of the. snow cap sur rounding it's southern pole. The disap- pearancc was due, of course, to the fact that it was summer in the south ern hemisphere of Mars, and tho polar snowa melted more and more rapidly as the sun rose higher upon them. Not, although the reason was plain, and be- cause it was plain, one could not watch the process without experiencing a strange feeling that amounted almost to awe It is quite easy, says the Sci cntinc American, to think dispaSsiou- ately of the possibility that some things may go on in other worlds just as they do in this one as long as your eyes have not confirmed what is in your mind; but when peering through telescope you actually behold such occurrences, the effect is startling, 1t is like com ing suddenly in broad daylight upon the scenery of dream. On June the snow around the south pole of Mars was 2,400 miles across. A snow cap of proportionate dimensions on the earth would, in the northern hemisphere eX- tend as far south as St, Petersburg, tho southern point of Greenland and Mount St Elias in Alaska, By July the di- ameter of the snowy area had dimin- ished to about .50O miles, On August l it was only l 100 miles and on August aF 1e ,1s,ss z. the southern hemisphere of Mars, the snow cap was but 800 miles across But heat accumulates in Martian summer after the sun has begun to decline, just us it does upon the earth, and accord ingly the melting of the snows eontin- ucd after the solstice was passed, At the end of September tho diameter of the snow-covered region was only about $50 miles, and at the opening of Noyem- Der it was less than 2Oo niles
 Now comes a curious fact, About the middle of October it was reported that She polar snow cap of Mars had van ished; some of the most powerful tele- scopes failed to reveal a trace of it! Yet it is not probable that it had actual iy entirely disappeared. The oNplana- ton of the apparent disappearance is no doubt to be found in the fact that as the snow area diminished it left the pole uncovered by receding to one side
 for previous observations have shown that on Mars, as on the earth, what may be called the pole of cold does not correspond in location with the pole of the planet axis Schiaparelli's observations in 1877 and 1879 showed that the center of the snow cap during its minimum in those years was dis
 placed toward that side of the pole corresponding 10 an areographc iongt- tude of about 70 degrees. With the other side of the planet turned toward the earth the snow cap would have been invisible, being so to to speak, hidden behind the pole. This is apparently just what occurred in the middle of October last. The south pole was then free from ice, and the center of the snowy region was displaced, as in 1877 and 1879, along the meridian of 70 degrees. But it was on the other side of She planet which was at that time presented toward the earth during the best hours for obser- yation, and consequently no polar snow
 was seen; not because it had no exist encc, but because it was concealed.
 IL is probable, however that at its minimum the snow cap was exceeding ly small, perhaps less than one hundred miles in diameter. No such rapid and and extensive disappearance of snow and ice ever occurs upon the earth, al though the advocates of an open polar sea may find encouragement in the fact that the uncovered south pole of Mars corresponds in color and general appearance with what are believed to be the water areas of that planet, while what remains of the snow cap in such circumstances rests apparently upon a mass of land, perhaps no more than an island rising out of the polar ocean. Owing to the larger eccentricity of its orbit the extremes of temperature on Mars are greater than upon the earth. although the total amount of the solar heat received by the planet is less than half as much as we get. But more im- portant than these differences is the rarity Of Mars atmosphere, which has been SO clearly demonstrated by the recent spectroscopie observations of Prof Campbell. 1t may not be scien- tifc, but it is certainly human to ask whether it is probable that human be- ings resembling ourselves were includ ed iu the field of view of our telescopes last autumn, while we watched the southern snows of Mars sparkling to the sun and melting away at his ardent touch. If such beings are there they must exist in an atmosphere less than One-quartcr as extensive as the earths