j882. '-^3 Tra>.s. N. V. Ac. Set. 



The result of this retardation would be a shortening- of the comet's 

 period ; and, after a few returns, the comet would not have sufficient cen- 

 trifugal force to overcome the sun's attraction, and so would plunge into 

 the photosphere. Although this plunge might be made at the velocity 

 of 200 miles per second (according to Proctor), yet no results disas- 

 trous for the earth are likely to follow. The study of the comets, at 

 their successive returns, shows us that they decrease in mass and size, 

 owing to the heat of the sun ; and moreover the mathematical astro- 

 nomers have never been able to find the least effect of the attractions of 

 the comets on the planets or satellites. 



Comets have been entangled among the satellites of our planets — 

 notably, Lexell'S comet of 1770, and have been swung off in the planets' 

 attraction to pursue totally different orbits. Yet the comets never af- 

 fected the motions of the smallest satellites, thus showing that the mass 

 of comets must be small compared with the planets and satellites. The 

 result, therefore, of a collision with the sun, might be only a solar dis- 

 turbance, which would evidence itself in a large spot and cause a dis- 

 play of auroras here, and the swinging of the magnetic needles. At 

 least the mathematical chances are in favor of some such slight dis- 

 turbance. But if this comet is to return in about six months, it may be 

 our good fortune to test the truth of these statements very soon. Per 

 contra, there are those among the astronomers who do not consider that 

 the identity of the comets of 1843, 1880 and 1882 have been proved. 



Mr. S. C. Chandler of Harvard Observatory points out the fact that 

 the orbit of the comet of 1843 was computed from observations after 

 its perihelion passage, and therefore after it had experienced all the 

 perturbing effect of the passage so close to the sun ; it was found 

 that it could not return for 175 years, and that the orbit of the comet ot 

 1880 was in like manner computed from observations after its perihe- 

 lion passage, and that comet cannot return for at least ten years. He 

 now computes the orbit of the present comet, representing all obser- 

 vations from nine days before the perihelion passage to thirty-two 

 days after it, and shows, not only that its orbit is an ellipse so ex- 

 tended that the comet cannot return for many years, but also that the 

 passage in close proximity to the sun did not materially affect the orbit. 

 This testimony is a severe blow to the theory of the identity of the 

 comets of 1843, 1880 and 1882. 



[The paper was supplemented by explanatory remarks in regard to 

 the chemical and physical constitution of comets. In the lantern exhi- 

 bition, the following points were dwelt upon. i. Connection between 

 comets and meteors. 2. Various forms of comets. 3. Observations 

 made on the tails of comets. Theory of a repulsive force emanating 

 from the sun. 4. The immense extent of the sun's " atmosphere " 

 through which some comets plunge.] 



