20 WRITINGS OF JAMES SMITHSON. 



salt and all superfluous vitriolic acid were driven off, .af- 

 forded 96.7 grs. of perfectly dry, or arid*^ white salt. On 

 re-solution in water, and crystallization, this saline matter 

 proved to ho wholly vitriol of zinc, excepting an inappre- 

 tiable quantity of vitriol of lime in capillary crystals, due, 

 without doubt, to a slight and accidental admixture of some 

 portion of the calcareous fragments on which this calamine 

 bad been deposited. Pure martial prussiate of tartar, 

 threw down a white precipitate from the solution of thia 

 salt. 



In another experiment, 20.0 grs. of this calamine afforded 

 28.7 grs. of arid vitriol of zinc. 



d. 10 grs. of this calamine were dissolved in pure marine 

 acid, with heat. On cooling, small capillary crystals of 

 muriate of lead formed in the solution. This solution was 

 precipitated by carbonate of soda, and the filtered liquor let 

 exhale slowly in the air; but it furnished only crystals of 

 muriate of soda. 



«. 10 grs. dissolved in acetous acid without leaving any 

 residuum. By gentle evaporation, 20.3 grs. i=: 2.03, of ace- 

 tite of zinc, in the usual hexagonal plates, were obtained. 

 These crystals were permanent in the air, and no other 

 kind of salt could be perceived amongst them. 



Neither solution of vitriolated tartar, nor vitriolic acid, 

 occasioned the slightest turbidness in the solution of these 

 crystals, either immediately or on standing ; a proof that 

 the quantity of lime and lead in this solution, if any, was 

 excessively minute. 



/. A bit of this calamine, weighing 20.6 grs. being made 

 red hot in a covered tobacco-pipe, became very brittle, di- 

 viding on the slightest touch into prisms, like those of 

 starch, and lost 5.9 grs. of its weight ■= 0.286. After this, 

 it dissolved slowly and difficultly in vitriolic acid, without 

 any effervescence. 



* Dry, as opposed to wet or damp, which are only degrees of each other, 

 merely implies free from mechanically admixed water. Arid, may be ap- 

 propriated to express the state of being devoid of combined water. 



