334 



SCIENCE. 



Head of Ponati's Comet, After Be 



THE COMET. 



The comet is daily becoming a fainter object, and 

 astronomers are now employed in making investigations 

 based on their observations. 



We understand that Pro- 

 fessor O. Stone, of Cincin- 

 nati, has published a state- 

 ment that he saw the nu- 

 cleus of the comet divide 

 into two parts. Professor 

 Stone is not one likely to 

 be mistaken in an obser- 

 vation of this nature, but 

 we understand he has not 

 been confirmed in this dis- 

 covery, as observations 

 since made with the large 

 equatorial at Washington 

 have failed to show any 

 division. A disturbance, 

 however, has been observed 

 in the nucleus, which Pro- 

 fessor Skinner considers 

 might be mistaken for a 

 division as described by 

 Professor Stone. 



On the 6th of July 

 the comet was ob- 

 served by Mr. Rock 

 of the Naval Observ- 

 atory, who thus, de- 

 scribes what he saw : 



" A bright tongue 

 of light about one 

 revolution long in di- 

 rection of tail, with 

 a slight node near 

 end and curved." 



In explanation of 

 this Mr. Rock said : 

 " I observed the 

 comet at the time of 

 its lower culmina- 

 tion about twenty 

 minutes after mid- 

 night. The nucleus 

 did not appear to be 

 divided, but a bright 

 band streamed out 

 in the direction of 

 the tail. This band 

 was about fifteen 

 seconds of the arc 

 in length. Near the 

 end of it was a bright 

 spot, and that por- 

 tion of the band ex- 

 tending beyond it 

 was curved in the 

 same general direc- 

 tion as the tail, but 

 in a somewhat short- 

 er arc. It is possible 

 that the observer at 

 Cincinnati was not 

 able to distinguish 

 the band of light 

 which I saw uni- 

 ting the nucleus and 

 the node, and so con- 

 cluded that he saw 

 two nuclei. When 

 I first observed the 



comet, on June 28, 



Comet of 1881. After Prof. Henry Draper's Photograph. 



the coma was apparently homogeneous as it also was on 

 July 2. On June 28, however, there were two spurs of 

 light spreading away from the opposite sides of the head 

 like angel's wings. On July 2, 1 did not observe these at 

 all or they were very faint. On July 6 I observed the 



appearance that I have de- 

 scribed. It may be that 

 this was the same thing 

 that I saw on June 28, 

 observed from a different 

 point of view. It is not 

 improbable, however, that 

 the nucleus has really di- 

 vided. Comets appear to 

 have a tendency to do that. 



To a correspondent of 

 the N. Y. Tribune, Profes- 

 sor Harkness said : 



" We think that the No- 

 vember meteors are the 

 debris of a comet which 

 first made its appearance 

 about the year 900. This 

 debris, to all appearance, 

 continues to trail along 

 the whole orbit of the 

 comet of which it formed 

 a part and which has 

 disappeared. The 

 August meteors are 

 assigned a similar 

 origin. Biela's comet 

 reappeared once 

 after its nucleus had 

 separated into two 

 parts ; it has never 

 been observed since. 

 All comets appear to 

 diminish in bright- 

 ness, and it is prob- 

 able that they be- 

 come gradually dis- 

 integrated. I have 

 undertaken spectro- 

 scopic investigation 

 of this comet, suffi- 

 cient to convince me 

 that the spectrum 

 is the same as that of 

 all comets. I made 

 observations on June 

 28 and July 1 and 2. 

 On June 28, I found 

 a bright continuous 

 spectrum with three 

 bands very hazy, the 

 whole indistinct. 

 Evidence of polari- 

 zation was not trust- 

 worthy, and I con- 

 cluded there was 

 no polarization. On 

 July 1 the spectrum 

 of the nucleus was 

 right, showing two 

 bands; wave lengths 

 approximately5 50.29 

 and 61 1.5. On July 

 2, I found a bright, 

 continuous spectrum 

 exten ding from 

 about wave length 

 577 to 428 ; the coma 

 gave three bright 

 bands ; wave lengths 



