308 New Elements q/'Encke's Comet. 



Dunlop, an ingenious maker of telescopes from Ayrshire, 

 who went out to New South Wales with His Excellency Sir 

 Thomas Brisbane, as a scientific assistant. Mr. Dunlop was 

 examining the heavens with a sweeper, when he encountei'ed 

 this singular body. We state this fact on the authority of 

 Sir Thomas Brisbane, who has recently transmitted to the 

 lloyal Society of Edinburgh a sei'ies of valuable astronomical 

 observations made at Paramatta. It is impossible to speak 

 too highly of the zeal and talents of this eminent astronomei*, 

 whose appointment to the government of New South Wales 

 has given such universal satisfaction. Great credit is due to 

 him in doing this justice to our modest countrj'man. Baron de 

 Zach, who considers the rediscovery of this comet as one of 

 the greatest efforts of modern astronomy, ascribes all the 

 glory of it to the " vigilant and penetrating eye of M. Rumker," 

 and to " Germanic diligence." M. Ruuiker has great merit 

 m every thing he does, and particularly in what he has done 

 on this subject; but the merit of discovering the comet is 

 solely Mr. Dunlop's. — Edin. Phil. Journ. 'col. vs.. p. 391. 



NEW ELEMENTS OF ENCKE's COMET. 



The following correct elements of this comet have been 

 given by M. Encke : 

 Passage of the perihelion, 1822, May 21, '01768, meantime 



at Seeberg. 



Longitude of the perihelion 157° 1 1' 28"*8 1 From mean 



'. i-^ node 331 19 31 -9 j equinox. 



Inclmation of the orbit, 



Excentricity 0-84454'79 



Its sine 57° 37' 24"-7 



Log. of one-half the greater axis... 0*3472191 



M. Encke is engaged in very laborious calculations, with 

 the view of ascertaining if the resistance of the ether could 

 have any influence in causing the diminution which has been 

 observed in its periodical time. — Edin. Phil. Journ. vol. xi, 

 _p. 39\,froni Zach's Corrrsp. Astron. vol. \'m. p. 279. 



ANSWER TO MR. J. HAMETT's QUESTION 

 [in our last Number, p. 236]. 



Newark, Oct. 9, 1823. 

 Although Mr. Harnett's question appears to rank among 

 tliose of the axiomatical class, yet I have endeavoui'ed to 

 comply with his wish by sending the following demonstration, 



which 



