Swiftest Of Known Moons

A aiewer and more accurate computation of Prof. Barnard determines the rué period oí the flying little moon to be 11 hours, 57 minutes and 22.56 seconds. It ílies around the glant planet at the wild rafce of 16.4 miles a second, a rate twelve times swifter th-an tliat oí little Phobos, the inner one oí the two satellites of Maivs. (These two little moons of Mars also were discovered by an American observer.) This íifth moon of Júpiter Ís not only very Binall- so siiKill, indeed, that even the space-penetrating eye of the giant refractor on Moiint Hamilton falte to reveal it as a dtsk, and leaves it a mere stellar polnt of llght- but it is also very near the great planet. Proí Barnard does not believe it can exceed, even if it equals. a diameter of 100 miles- fruly a wonderful speek to see, by an observer stationed on our fílobe, gaziog throngh a profound gulf of space about 400,000,000 of miles deep ! And the tiny object is ílying around the deep, majestic orb oí Júpiter at the 1 , ■ ,■ i s t possible distance consistent with its own safety ; for it is found to lie at a distance of 57,000 miles írom Jupiter's surface, just outside a certain limit, inside of which, it seems, no satellite could exlst, because oí the enormous attractive power oí the great planet, which would pretty certainly tear the little moon to pieces. It is also coinputed pretty certalnly that any freely movable object on the surface oí thls newly discovered moon, as a man, a chair, a cavt, etc., must be instantly drawn (or rather huiled) through the 67,000 interventag miles directly to the big planet as soon as Júpiter rtees above the horizon of any such object. A man on that satellite would have to be anchored with so-mething heavier than Senator Stewart's long silver speech il he would avoid a cannon-ballflight tu Júpiter, with the prospect of being daslied to bits om landing. And then he would still be over 40,000 miles trom the center of the great [ilanet, so vast is its bulk. Indeed, the little mooni is believed to be already losing its bulk, in the shape of various materials drawn oíl into a ring ; a thin ring like one oí Saturn's encircllng Júpiter, but, as yet invisible írom the earth. It may be true. Even to be drawn into a ring would not hurt so bad -as to go the whole distance of the plunet itself. There are those who think that our earth was once encircled by a bright ring. The only satellites the world has ever known as belonging to Júpiter - until i'roi. Barnard's interestang di.scoTery- were the ïour that Uallileo discovered, with that little '-optie glass" of his, as ïlilton somewhere oalls that pioneer spyglass, in the year 1610. The tTurü óf those foui' satellites is over 3,400 miles in diameter- or as big probably as the