Adulteration of Tea. — New Analysis of Camphor. 151 



tion of ammonia in, the Natrolite of Hohentwiel, as well as in 

 the Clay Porphyry in which it occurs in veins. 



Prof. Gmelin determined that the pinite he examined did 

 not contain any fluoric acid ; and thinks that his analysis sub- 

 stantiates such an affinity, with respect to chemical composi- 

 tion, between pinite and mica, that they must no longer be 

 considered as generically separate. The circumstance that 

 pinite contains no fluoric acid, cannot be considered as an 

 essential difference ; because H. Rose has shown that those 

 varieties of mica which occur in primitive limestone, either 

 contain only a minute quantity of that acid, or are altogether 

 free from it. — Kastner's Archiv.f d. ges. Naturlehre. Band i. 

 p. 221, 226. 



ADULTERATION OF TEA. 



To the Editors of the Philosophical Magazine and Journal. 

 Gentlemen, 



I know not whether you may deem the following worthy of 

 notice in your Magazine ; it appears to me a curious instance 

 of Chinese adulteration, which must upon the whole prove a 

 considerable loss to the consumers of tea. 



I have for some months observed a black sand settle at the 

 bottom of my tea-cup, but more abundantly in the basin that 

 receives the water first poured out of the tea-pot : upon exa- 

 mining it carefully a few days ago I found it to contain mag- 

 netic iron in minute crystals. The same substance was soon 

 observed adhering to the leaves of the black tea in the caddy, 

 sometimes in quantity sufficient to enable a magnet to raise 

 small portions of leaves. Upon macerating some closely 

 twisted masses, a considerable portion of sand was separated 

 that had evidently been introduced while the leaves were fresh. 

 It has been found in black tea of various prices. 

 Yours very truly, 



2, Mead Place, Lambeth, J. De C. Sower by. 



Aug. 20, 1824. 



NEW ANALYSIS OF CAMPHOR, BY DR. GOBEL. 



The results of Dr. Giibel's analysis of this substance are as 

 follows : 



Carbon .... 74*67 

 Hydrogen . . . H'24- 

 Oxygen .... 14*09 

 100-00 

 According to Saussure, camphor contains a small quantity 

 of nitrogen; whilst the analyses of Doctors Thomson and Ure 

 agree with Dr. Gobel'fl in not indicating the presence of that 

 substance* — Schvaeigger's Neues Journal, Band x. p. 356. 



CONTRACTIONS 



