106 



to be seen without the help of a lens : others, however, may 

 be seen without one, three in particular, as figured. Hi- 

 therto crystals of Oxide of Zinc have been but little noticed 

 in Great Britain. Mr. Smithson, in Phil. Trans, for the 

 year 1803, part i. 17. after speaking of a yellowish Calamine 

 from Derbyshire not electric, says of Electric Calamine — 

 t( that the Abbe Haiiy has considered this kind as differing 

 from the other Calamines only in the circumstance of being 

 in distinct crystals; but it has already appeared, in the 

 instance of the Derbyshire Calamine, that all the crystals 

 are not electric by heat, and hence, that it is not merely 

 to its being in this state that this species owes the above 

 quality. And the following experiments on some crystals 

 of electric Calamine from Regbania in Hungary, can leave 

 no doubt of its being a combination of Calx of Zinc with 

 Quartz ; since the quantity of Quartz obtained, and the 

 perfect regularity and transparency of these crystals, make 

 it impossible to suppose it a foreign admixture of them. 

 They were not scratched by a pin; a knife marked them. 



" According to Pelletier's * experiments on the Calamine 

 of Fribourg in Brisgaw, which is undoubtedly of this 

 species, its composition is : 



Quartz . . . 0*50 

 Calx of Zinc . 0'38 

 Water . . . 0-12 



1-00 



and according to his own experiments : 



Quartz . . . 0*250 



Calx of Zinc . 0-683 



Water . . . 0-044 



Loss .... 0-023 



l'OCO 



* Journal de Physique, vol. 20. 434. 



