PHYSICAL AND LITERARY. 389 



with powder of galls, it immediately gave 

 a blue tin(5lure. 



13. I boiled a chopin of this fpaw wa- 

 t6r, in a clean tin pan, till there remain- 

 ed of it only one fourth part ; it turned 

 of a yellowifli colour and was muddy : 

 When this was cold, and the okry flakes 

 precipitated, it had a harfher and more 

 aluminous tafte than the frelh fpaw wa-* 

 ter, or than that which had been fo long 

 expofed to the air (12). To a glafs of 

 this, I put powder of galls ; it changed 

 very flowly, and, after it had flood about 

 eighteen hours, it exhibited a faint blue. 



14. I M a clean tin pan, over the fire, I 

 evaporated a chopin of the fame fpaw 

 water, till there remained only about one 

 ounce and a half; this I immediately 

 poured into a china tea- cup, and, when 

 cold, filtrated it : The filtrated liquor was 

 clear and limpid, and had a flrong chaly- 

 beate tafte ; this was evaporated by a 

 fand-heat, in a wide -mouthed glafs ; there 

 was left a fait of a whiciili brown colour, 

 which had an aluminous and flrong cha- 

 lybeate rough tafle. The whitifh brown 



colour 



