The Moons Of Mars

[Fronl hè Now York Tribuno.] A disoovcry that will rauk among the most important in ustronomy haa just been made nt Washington, by Prof. Aeaph Huil. The planet Mars, since the inventiou of the telescope, has proved more conv.enient for examination, and tliere is more known about it than any other celestial objeot, not eveu excepting the moon, since óf that only one side is ever turned toward us. Venus, thongh nearer us tlian Mars, is never seen to as great advantage. All who have studied the charaotenstics of Mars have been struek by its similarity in many partioulars to the earth; sucn as having continente and sea; frozen poles where the progresa of winter and summer can be alternately traced; a day of nbout the same length as ours; an atmosphere over portions of which clouds are tiitting. But the ace hing in which Mars was supposed to difler totally from the earth was the absence of a moon. That reproach is now taken away from the red planet, tlianks to the twenty-sixinch refractor at the United States Naval öbservatory, and the labors of Prof. HalL At the present time Mars, is in a better position for close o"bservation than has been the case for several years. The relracting toleseope of the observatory s the bebí instrument of its kind which hos ever boen tumed toward the sky. Yet in the hands óf less experieneed and alert observers this discovery would never have been made. For, stmnge to say, the existencc of a satellite of Mars had not been snspected, whilo the traditions of modern astoronomy are rife with specnlation as to such a companion to the planet Venus. The question now is, not whether Mars has a satellite, but whother it has two. This great triumph, whieh will go down into history along with Herschel's discovery of Uranus and La Vt'rrier's prediction of the existence and place of Neptune - is purcly American. It is not the flrst triumph of the great refractor, whose object-glass is probably the most perfect x'iece of workmanship that Alvan Olark fc Sons, oí Cambridge, Miiss.,have ever produced, for tliut instrumefnt signalized its entryinto the field of research by determining thp inimbc r of the moons of Uranns. That, though iniportant to astronomical science, wtis not a discovery with any ultirmito boM-ings. Tl ie fnct that Mars has one or more satellites wiü be hailed as a new proof of tlie nebular hypothesis, fta their supposed absence hail been urged as one of the weaknesses of that theory. M'JIY TJIKV' HAVIÏ NOT HKKX DISCOVEKED BFJFORE. i u 'ui-hiiiKlon t'or. Chicago Tribune] Prof. Newoomb, of tho Naval Observatory, gives the following additional intcrestiiiR facts relativo to the discovery of the moons of Mars : The reason why these moons have not been seen bef ore is that Maïs is nearer to the earth than it bas been at any time sinoe 1845, when the great telescopes of the present day had hardly begun to be known. Tho next opportunity occurred in 1862, but the satellites did not scem to have beej] especially songht for by tho two or three telesoopes which alone coidd show thern. The most favorable position was in 1875, but Mars was then so íar soutli of the equator that it could not be observed in onr latitude. The present is about the firBt position for observution in tlie middle latitudes of our heinisphere. The next opportunity will occur in October, 1880, after which the satellites will probably be entirely invisible for ten yeara. Prof. Newcomb regards this planet, perhaps, as among the most remarkable of the solar system,