Chap. 27.] White Vitriol 151 



point they are covered with a fkin, which prevents 

 their union. 1 he calx of zinc is not very eafily re- 

 duced to a reguline it ate, as the heat neceffary for this 

 effect is apt to volatilize the metallic product. 



Zinc is readily acted on by all the acids, and no 

 metal mews a greater attraction for them. It pro- 

 duces with them metallic faits, in which the acid is 

 more neutralized than in the o:her metallic compounds 

 of the fame description. The acids do not depofic 

 the zinc when they are diluted with water. 



The concentrated vitriolic acid does not act on zinc, 

 unlefs affifted by heat, and it then gives out fulphu- 

 reou$ fumes. Ic is difTolved, however, with rapidity, 

 and without the afTiftance of heat, by the fame acid in 

 a diluted ftate, and this procefs is attended with the 

 copious produdion of hydrogen gas, which indicates 

 the decomposition of the water. From this folution 

 may be obtained white vitriol, which, as well as the 

 flowers of zinc, is employed in medicine. 



The diluted nitrous acid acts on zinc with fingular 

 violence, and nitrous gas is fo copioufly difengaged, 

 that the mixture fometimes exhibits the appearance 

 of boiling. The folution is very cauftic, and affords 

 cryftals by evaporation and cooling, which (lightly 

 detonate on hot coals, and leave a calx behind. This 

 fait is deliquefcent. The diluted muriatic acid acts 

 on zinc with the fame production of hydrogen gas. 

 as the vitriolic j but this folution does not afford cryf- 

 tals. , 



The vegetable acids acquire from zinc a fweetifh 

 tafte and ftipticity. The action of the fluoric and 

 boracic acids on zinc are not known. Water impreg^- 

 rated with carbonic acid, diflblves a confiderable pro- 

 porrion of zinc. 



All the folutions of zinc in acids are precipitated 



by lime, magnefia, the fixed and volatile alkalis > the 



L 4 latter 



