WRITINGS OF JAMES SMITHSON, 19 



tongue ; 68.0 grs. of it, in small bits, immersed in distilled 

 water, absorbed 19.8 grs. of it, = 0.29. 



It admitted of being scraped by the nail though with 

 some difficulty : scraped with a knife, it afforded no light. 



68.1 grs. of it, broken into small pieces, expelled 19.0 grs. 

 of distilled water from a stopple bottle. Hence its density 

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

 FAHRENHEIT, displaced 5.27 grs. of distilled water; hence 

 the density = 3.598. The bits, in both cases, were entirely 

 penetrated with water. 



b. Subjected to the action of the blowpipe on the coal, it 

 became yellow the moment it was heated, but recovered its 

 pristine whiteness on being let cool. This quality, of tem- 

 porarily changing their colour by heat, is common to most, 

 if not all, metallic oxides ; the white growing yellow, the 

 yellow red, the red black. 



Urged with the blue flame, it became extremely friable ; 

 spread yellow flowers on the coal ; and, on continuing the 

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

 directed against the flowers, which had settled on the coal, 

 they shone with a vivid light. A bit fixed to the end of a 

 slip of glass, wasted nearly as quickly as on the coal. 



It dissolved in borax and microcosmic salt, with a slight 

 effervescence, and yielded clear colourless glasses ; but 

 which became opaque on cooling, if over saturated. Car- 

 bonate of soda had not any action on it. 



c. 68.0 grs. of this calamine dissolved in dilute vitriolic 

 acid with a brisk effervescence, and emitted 9.2 grs. of car- 

 bonic acid. The solution was white and turbid, and on 

 standing deposited a white powder, which, collected on a 

 small filter of gauze paper, and well edulcorated and let 

 dry, weighed only 0.86 gr. This sediment, tried at the 

 blowpipe, melted first into an opaque white matter, and then 

 partially reduced into lead. It was therefore, probably, a 

 mixture of vitriol of lead and vitriol of lime. 



The filtered solution, gently exhaled to dryness, and kept 

 over a spirit-lamp till the water of crystallization of the 



