The daily morning journal and courier., 1896-07-14
course it would be understood that such

uler was able to do, therefore, was not In the nature of absolute proof, but rather the calling of attention to probability which further observation might prove or disprove. Lexells com ct, which takes it's name from the as- tronomer who computed It's orbit, was first seen by the French astronomer Messier in 1770 Soon after discovery it became very brilliant, much more so than any of our comets for twenty years or more. This brightness was due to the fact that in the orbit in Which 1t was moving it approached to within million and half of miles of the earth. It was observable through about four months and the opportunity was therefore given of computing an orbit which could represent it's path quite accurately. This was done by Lexell, who showed it to be moving in an orbit of about five and one-half years period. The comet was watched for when due, and time after time passed when it ought to have been seen. But at that time or since no trace of 1t has been found unless the Brooks com ct should turn out to be identical with 1t. Lexell found that in 1779 the comet came very close to Jupiter, and sup posed that approach perhaps to be the reason for it's disappearance.
 Dr. Chandler began his Investigations by computing an orbit for the Brooks comet, which he found to be moving in an ellipse, the outer end of which just touched the orbit of the planet Jupiter, and this ellipse required a period of seven years and a few days to com plete. Carrying back this motion few years, he found that in 1886 the object was very close to Jupiter, so close as to have had the shape of it's orbit modi- fed Carrying the computation back still further, other notifications in mo- tion were probable until a history of the object was secured which was the best possible with the material availa- ble The story is this: When Lexell lost sight of his comet it was moving in an orbit of about five and one-half years period. This motion brought it within disturbing distance of Jupiter in 17SS, it having made an unobserved return to the sun in the meantime. The effect of Jupiter's attraction was to turn the comet into an orbit about it. self, so that for eight months 1t re- mained entangled among its moons. At that time the attraction which the sun had for the comet was but slightly greater than that of Jupiter for the same object, so that the comet narrow I ly escaped being thrown into an orbit about Jupiter, and becoming for a greater or less space of time a true sa- tellite Of his celestial majesty This, | however, did not occur, but it has giv en rise to some new thoughts about sa- l tellites, and some Investigators have even been led to discuss the question whether the fifth moon of Jupiter, the one which was discovered a few years ago by Barnard, might not be in truth some recently captured body which came under the influence of the great planet in much the same way as did Lexells comet
 But after all, the influence of the sun was more potent than that of Jupiter, and the comet decided to continue it's course about old Sol, but as parting memento Jupiter bestowed upon 1t such a perturbation as to give it's orbit an altogether different shape, a long el- l lipse of twenty-seve years period, the extremity of which extended out to- l wards or quite to the path of Saturn. | Through this third and longer orbit the l comet moved for number of periods, | returning again and again to the sun, l until in 1886, little more than three years before it was seen by Brooks, it was again disturbed by Jupiter and l turned into it's present orbit, it's fourth one, through which it now moves, re- | quiring seven years for 8 full circuit. All of this computation was undertaken by Dr. Chandler, an investigation of much labor and great merit, which was carried out as accurately as the data would permit The result is not a cer-
 tainty, nor does Dr. Chandler claim it
 to be such, butsit is probability which
 needs further observation of the comet to prove or to dispose of. The observa-
 tions of the present appearance will gc
 very far towards furnishing material
 for more refined consideration of the
 delicacies of the problem. The future
 of the comet is fairly we'll determined
 for a number of years, and the returns
 of 1896, 1903, 1910 and 1917 will probably
 be strictly according to schedule, but 1T
 1921 it will again be close to Jupiter, SC
 close as to be again disturbed. By
 that time, however, the orbit will be SC
 well determined that the resultant mo.
 tion will be readily computed.
 Of course the presence of periodica
 comet in the sky was the cause fol
 quite little activity among astrono
 mers, half @ dozen of whom took live
 ly interest in the stranger. A spell oi
 cloudy weather followed the discovery
 of the comet by Brooks in July, 1889
 and not until the 22d was it possible tc
 publish any orbits. A preliminary on,
 was prepared which served its immedi ate purpose of aiding astronomers ii
 setting their telescopes upon it. Thi is a very necessary feature, for th'
 large instruments cannot be used t .. sweep over an indefinite space to find ; , thing; they must have a pretty clos
 position for economy of time and tn best work. This service is carried ol by the Science Observer Circulars 0 Boston, which stand ready to print ant
 circulate the early orbits of comets tn moment the figures are ready to b
 published. In this case the earliest or
 bit was computed by Dr. Chandler
 while a few days later the Rev. G. M
 Searle of Washington and Dr. Chandle
 each furnished orbits which followed
 tho a1lintjcal track of fha comet Flo