WRITINGS OF JAMES SMITHSOF. 21 



According to these experiments, this calamine consists oi 



Calx of zinc 0.714 



Carbonic acid 0.135 



Water 0.151 



1.000. 



The carbonates of lime and lead in it are mere accidental 

 admixtures, and in too small quantity to deserve notice. 



Calamine from Somersetshire. 



a. This calamine came from Meudip Hills in Somerset- 

 shire. 



It had a mammillated form ; was of a dense crystalline 

 texture ; semitransparent at its edges, and in its small frag- 

 ments; and upon the whole very similar, in its general 

 appearance, to calcedony. 



It was tinged, exteriorly, brown ; but its interior colour 

 was a greenish yellow. 



It had considerable hardness ; it admitted however of 

 being scraped by a knife to a white powder. 



56.8 grs. of it displaced 13.1 grs. of water, at a tempera- 

 ture of 65 FAHRENHEIT. Hence its density = 4.336. 



b. Exposed to the blowpipe, it became opaque, more 

 yellow, and friable ; spread flowers on the coal, and con- 

 sequently volatilized, but not with the rapidity of the 

 foregoing kind from Bleyberg. 



It dissolved in borax and microcosmic salt, with efferves- 

 cence, yielding colourless glasses. Carbonate of soda had 

 no action on it. 



c. It dissolved in vitriolic acid with a brisk effervescence ; 

 and 67.9 grs. of it emitted 24.5 grs. 0.360, of carbonic 

 acid. This solution was colourless ; and no residuum was 

 left. By evaporation, it afforded only vitriol of zinc, in 

 pure limpid crystals. 



d. 23.0 grs. in small bits, made red hot in a covered- 

 tobacco-pipe, lost 8.1 grs. 0.352. It then dissolved slowly 



