where P = 



CONTRIBUTIONS TO BLOWPIPE ANALYSIS. 339 



2 sin A sin B sin C* 

 To find the value of H, we have, since (/, ^,|A) is the centre, 

 uf vg wh 

 a h c 



therefore 



and also 



Hence 



Hence, finally, we have the quadratic, in which the values of r* are 

 the squares of the semi-axes of the conic, 



» sin 2 J. , , , 



== 5 + anal 4- 



sin 2 A 

 where 



1 2 sin ^ sin B sin C ia^ 



F (2 A) = 



I— + — + -I. 



\u V w f 



Uhivbbsitt College, 

 October 25th, 1865. 



\ 



J. B. C. 



CONTRIBUTIONS TO BLOWPIPE ANALYSIS. 



BY E. J. CHAPMAN, Ph.D., 



PHOPBSSOE OS MINEEALOGT AND GEOLOaT IN UNITEESITY COLLEGS, TOEONTO. 



The following notices comprise various blowpipe-tests and appli- 

 cations published by the writer within the last eighteen or nineteen 



