PACIFIC AND BEERING'S STRAIT. 19 



ated to the S. E. of the square formed by e^p Ceti. 

 The head had a bluish cast, and increased in lustre 

 towards its nucleus, where indeed it was so bright, °825.' 

 that with our small telescopes it appeared to be a 

 star ; but this was evidently a deception, as Mr. 

 Herschell, who made some interesting and satisfac- 

 tory observations on the same comet, found on turn- 

 ing his twenty feet reflector upon it, that the star- 

 like appearance of the nucleus was only an illusion.* 

 The tail extended between 9° and 10° of arc in a 

 N. W. direction, and gradually increased in width 

 from the nucleus till near its termination. We 

 made a number of measurements to ascertain its 

 place, and continued them every night afterwards 

 on which the comet appeared ; but as its orbit has 

 been calculated from far more accurate observations, 

 and ours were necessarily made with stars unequally 

 affected by refraction, which involves a laborious 

 reduction, besides the abstruse calculation for deter- 

 mining its orbit, I have not given them a place. 



On the following night we noticed distinctly the 

 bifurcation of the tail represented in the Memoirs 

 of the Astronomical Society. The branches were 

 of unequal length, and the lower one diverged from 

 the nucleus, at an angle of about 40°. 



On the 6th we made the island of Mocha, on the 

 coast of Chili, a place once celebrated as a resort of the 

 Buccaneers, who anchored off it for the useful supplies 

 which in their days it furnished. Its condition was 

 then certainly very different from the present : seve- 

 ral Indian chiefs and a numerous population resided 

 there, and it was well stocked with cattle, sheep, 



* See Memoir Ast. Soc. vol. ii. p. 2. 

 C 2 



