Constituents of various Minerals. 263 



which he separated, with sufficient accuracy to be sure of his re- 

 sults. The art of analysis is soon learnt, when the pupil has pre- 

 viously made himself acquainted with the general principles of 

 chemistry. I have had pupils who could analyze with great ac- 

 curacy very difficult minerals, after less than a year's practice. 



Leelite is obviously a compound of octosilicates, consisting of 

 2AlS 8 +fS 8 + KS 8 ; or 



2 atoms octosilicate of alumina, 

 1 atom octosilicate of iron, 

 1 atom octosilicate of potash. 



It certainly differs from compact felspar. 



12. Bucholzite. 



The first account of this mineral was published in 1819 by 

 Dr BRANDES, in the 25th volume of the first series of SCHWEIG- 

 GER'S Journal. He had obtained it from Professor WEISS, and 

 its locality was the Tyrolese Alps. BRANDES gives an analysis 

 and very imperfect description, and I have seen no farther ac- 

 count of the mineral in any mineralogical treatise since publish- 

 ed. About three years ago, Mr NUTALL was kind enough to 

 send me some minerals from the United States. One of these 

 from Chester on the Delaware, south-west from Philadelphia, he 

 called Bucholzite, on the authority of Mr HEULAND. About a 

 year ago, I got new specimens from him from the same place, 

 which were larger, purer, and better characterized. 



The colour of Bucholzite is greyish-white, with a very slight 

 tinge of yellow, not recognizable in the purest specimens. 



It is composed of fibres which in some places appear curved, 

 and, when viewed through a glass, assume the appearance of 

 plates or imperfect crystals. 



Lustre silky. 



