20 



THE POPULAR SCIENCE MONTHLY 



The prediction for the next return was taken in hand, in due time, 

 by no less than four distinguished mathematicians — Damoiseau, Ponte- 

 coulant, Lehmann and Rosenberger. These found, respectively, for the 

 time of perhelion passage, 1835, November 4, 13-15, 26 and 12. This 

 time the perturbations due to Uranus and the earth were included as 

 well as those of Jupiter and Saturn. The actual time proved to be 

 November 16. 



Search for the comet began, on the part of numerous comet seekers, 

 as early as January, 1835, but the first sight of it was obtained August 

 5, by Dumorchel, at Rome, very near the predicted place. About the 

 middle of September, two months before perihelion, it became visible 

 to the naked eye. The greatest brilliancy occurred about the middle of 



Halley's Comet as photographed with the Two-foot 

 Keflector of the Yeekes Observatory. 



October. The public had been expecting something very striking, but, 

 unfortunately, cloudy weather interfered to a great extent. It prac- 

 tically disappeared from the northern hemisphere with perihelion pas- 

 sage, but was followed for some time longer by Sir John Herschel at 

 the Cape of Good Hope. 



As regards the present appearance, the comet is already with us. 

 The preliminary searching on this occasion has been greatly facilitated 

 by photography, a resource not available on previous occasions. More 

 than a year ago, as soon as this region of the sky had fairly emerged 

 from the sun's rays, the campaign began at a number of observatories, 

 in this country and Europe. The results were negative. Dr. Wolf, of 

 Heidelberg has the honor of being the first to detect the comet on one 



