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Show THE SrECTEOSCOPl:;. A New Una for the Instrument Heofcntly Discovered. Ii Can M3ur the 7fiDr6n3e2ti of lha Sts.s a; VTcii ss Tfccir Cunipoii-lien Cunipoii-lien Tcs reculiaritic. cf a Ceieirisl r.eznss. As an instance cf the extraordinary results obtainable by the use of the spectroscope Sir Robert Ball describes how astronomers have at last got e'iual witn the vagaries of Algol the demon star. The peculiarities of this celestial demon are that for two days and fen hours 1 he star remains of uniform luster, lus-ter, being ranked about the second magnitude; then a decline cf brightness bright-ness sets in and the star in a few hours parts with three-fifths of its brightness. bright-ness. These changes are visible to the naked eye and have been known for centuries. But. nobody knew how to account for them. At last, adds the Pall Mali Budget, Vogel lias made the star reveal its mystery: "Applying the improved speetogfraph-ic speetogfraph-ic process to Algol, he determinedon one night that Algol was retreating at a speed of twentyr-six miles a second. When he repeated his observations he found that Algol was again moving with the same velocity, but this time the movement was toward the earth instead in-stead Of from it. Now-, it is. impossible for a star to run along a straight line for a certain distance, stop, turn back, again retrace its movement, stop and again return. Such movement is simply sim-ply forbidden by the laws of motion. But there is no obiectiou to the supposition sup-position that Algol Is moving in a path which is nearly if not exactly a circle. During the description "of one semicircle semicir-cle Algol is coming toward n3, while during the oihe-r semicircle it is going from us, and thus the observed facts of the movement are conciliated with the laws of motion " But the results of the new astronomy in connection with Algol are not exhausted ex-hausted yet. isueh a movement as has been above proved admits of no other interpretationcsave thut there must be another mighty body in the immediate vicinity of Algol. "We have already seen reason to believe be-lieve in the possibility of the presence of such a companion for the demon star, simpiy from the fact cf its variability. varia-bility. There cannot be any longer a doubt tunt the mystery has been colved. Algol must be attended by a companion compan-ion stcr, which, if net absolutely cs devoid de-void of intrinsic light cs the earth or the moon, is nevertheless dark, relatively relative-ly to Algol. Ones In each period of revolution this obscure body intrudes betsveen the earth and Aiol, cutting-off cutting-off a portion of the direct light from the star and thus producing -the well-known well-known effect. " But tiiS evr t;trcnoyiy not only proves the existence of ihistiii-eer. star; it- measures T.nd weighs it cs well. "Here is zn o'ejset,'' cay; Sir Ecccit Bail, which we htrre nevr 3'-3" znl yet we hr-s iztz. cclo io sift it, to |
