Morning journal and courier., 1881-09-13
The Great Comet of 1881.
Unknown Heretofore, 1t Will Not Return for Thousands of Years, if Ever-What Was Learned of 1t.


 for Thousands of Years, if Ever-What
 Was Learned of 1t.
 From the Philadelphia Ledger.l
 HAvERFoRD COLLEGE OBSERVATORY, Ninth Month, Sd, 18S1.-The great comet Comet B, 1S81) being now, except in telescopes, a thing of the past, 1t may be well to gather to- gether the results obtained by different scientific from their studies of it. The comet was seen by the naked eye in South America and Australia at least month before it was observed here It was then much fainter object than when it had arrived at it's perihelion, which was about coincident with the date of it's northern discovery Good obseryatories exist at Rio Janeiro, Cordoba, in South America, and at Melbourne and Sid ney, in Australia. The observations of it taken in these places in it's incipient stage, while not revealing anything new as regards its constitution or structure, have been valu- able in deducing the form of its orbit and it's identity with previous comets. The northern observations have been more varied and pro- ductive. They may be divided into CD measurements of position by micrometer and transit instrument CD drawings, showing it's physical appearance and changes made by the aid of telescopes of good defining power; (3) spectroscopic observations, for the pur- pose of ascertaining it's structure and chemi- cal composition; '(4) photographs.
 The first of these was for the purpose of gaining data for a computation of its orbit The results, so far at present .deduced, show that the comet moves in 8 parabola, or in very much f1attened ellpse and that if it ever returns it will only be after the lapse of thousands of years. They also show that if it has ever been here before there is no record of it so well authenticated as to iden- tify the two objects. The bright comet of 1907 has elements which very much resemble those of our recent visitor. But Bessel, one of the most reliable and careful of comput- CTS, gave it an orbit which would not bring it around again till after the lapse of about 1, ,5OO years, and the. points of dissimilarity are too great to be reconeiled; so that the identity of the two is certainly not estab- lished. It has been suggested with great plausibility that they were originally con- nected, and that, as in the case of Biela's comet, in 1846, they have parted company, and got so far separated that one precedes the other by period of "A years. The inti- mate connection between meteors and con- cts makes all kinds of differences from one to the other justifiable, and it is certain that me- teoric bodies chase each other round and round in similar orbits, and that they are probably formed by the disruption of great comets. Our comet may, then, be fraction al part of still greater comet which long ago was forced by some internal convulsion to shift for itself, and which has since followed the wake of its parent through space.
 The second class of observations were those going into the details of it's physical appearance. They have shown that violent forces have been continually acting within, and render the disruption theory probable The Cincinnati observers at one time an- nounced it's split. But by the time other ob servers had the opportunity to examine the difference was healed, or the smaller member had faded away, so as not to reach the digni- ty of a separate comet Great streams of luminous gas would issue from the nucleus Envelopes would form themselves around it and be dissipated. The masses of haze sur rounding it would show eyer-changinp shapes, and all appearances would indicate strong forces operating within it's mass. which forces were stirred into life by ap- proach to the sun and diminished by reces- sion. There have been made-some of them published and some filed away in obser- vatory records-a number of drawings of it's different appearances, which some day will be valuable foundations for theories con- corning it's nature and structure.
 The spectroscopic observations have given, in the words of William Higgins, the great English authority in this line of work, the following results: Part of the light from comets is reflected solar light, and another part is light of their own. The spectrum of this light shows the presence in the comet of carbon, possibly in combination with hydro gen." The nucleus is probably solid, and re- fleets solar light, just as the moon does, while the streamers, the envelopes and the tail are masses of carbon or hydro-carbon gases, emitting light of their own
 Besides the proof of the fact that comets l can be photographed, the results obtained by | the camera in photographing the comet itself | are not very valuable. It would at first ap- pear that the impression would be more ae- curate in it's details than any draw ing could possibly be-. And so it would if the exposure could be only momentary. But in the half-hour or the hour of necessary exposure the details of the head may have greatly changed The result is that no very definite photographs of the outlines of the head have been obtained, and that the draw ing will continue to be the reliable means of knowing it's appearance at any moment But the, photographs of the spectrum are of the highest utility, affording the means of leis- urely and certainly determining the position of the bright lines and the character of the substances which produce them, and enab- ling spectroscopists to compare with one another their charts.
 Such is brief summary of results ob- tained from this productive comet. Never was one more carefully observed or by better observers or instruments. Nothing new as to comets in general has been obtained, but old theories have been established and mass of observations taken which some day will much assist in settling the still enigmat-