CHEMICAL ANALYSIS OF SOME CALAMINES. 75 



68.1 grs. of it, broken into fmall pieces, expelled 19.0 grs. Specific gravity, 

 of diftilled water from a ftopple bottle. Hence its denfity 

 = 3.584. In another trial, 18.96 grs. at a heat of 65" Fahren- 

 heit, difplaced 5.27 grs. of difiilled water; hence the denfity 

 = 3.598. The bits, in both cafes, were entirely penetrated with 

 water. 



b. Subjefted to the adtion of the blowpipe on the coal, it be- Blowpipe aflays. 

 came yellow the moment it was heated, but recovered its priftine 

 whitenefs on being let cool. This quality, of temporarily 



changing their colour by heat, is common to mofl, if not all, 

 metallic oxides ; the white growing yellow, the yellow red, the 

 red blaclc. 



Urged with the blue flame, it became extremely friable ; 

 fpread yellow flowers on the coal ; and, on continuing the fire 

 no very long time, entirely exhaled. If the flame was dire6ted 

 againft the flowers, which had fettled on the coal, they (hone 

 with a vivid light. A bit fixed to the end of a flip of glafs, 

 wafted nearly as quickly as on the coal. 



It diflblved in borax and microcofmic fait, with a flight 

 eflfervefcence, and yielded clear colourlefs glaflfes ; but which 

 became opaque on cooling, if over faturated. Carbonate of foda 

 had not any a6tion on it. 



c. 68.0 grs. of this calamine diflblved in dilute vitriolic acid Solutions h the 

 with a briflc effervefcence, and emitted 9.2 grs, of carbonic mj'riat"c''adds 

 acid. The folution was white and turbid, and on ftanding gave only falts of 

 depofited a white powder, which, colkaed on a fmall filter ^^J^^J^^^ save 

 of gauze paper, and well edulcorated and let dry, weighed 



only 0.86 grs. This fediment, tried at the blowpipe, rnelted 

 firft into an opaque white matter, and then partially reduced 

 into lead. Il was therefore, probably, a mixture of vitriol of 

 lead and vitriol of lime. 



The filtered folution, gently exhaled to drynefs, and kept 

 pver a fpirit-lamp till the water of cryftallization of the fait and 

 all fuperfluous vitriolic acid were driven oflT, afforded 96.7 grs, 

 of perfe6tly dry, or arid*, white fait. On re-folution in water, 

 and cryftallization^ this faline matter proved to be wholly vitriol 



* Dry, 3,5 oppofed to wet or damp, which are only degrees of 

 each other, merely implies free from mechanically admixed water, 

 Arid, may be appropriated to exprefs the ftate of being devoid of 

 combined v/ater. 



