at Ltthifigton Priors. 257 



tit. SOME ANOMALOUS APPEARANCES WITH PRECIPITANTS. 



1. After the fpontaneous precipitate has been feparated, 

 4 little oxygenated muriate of mercury was diflblved in a 

 glafs full of the water. A white matter feparated during 

 the folution, and, in fome hours, collected in confiderable 

 quantity. 



2. A piece o'f fulphale of argill was dropped into a jar of 

 the fame water ; prefently a ftratum of white matter was 

 formed at the bottom of the jar : but this appearance is tran- 

 fitory ; for in the courfe of an hour or two the precipitate is 

 re-difiblved, and the water refumes its tranfparcncy. This 

 is an 'appearance which I had not found noticed by writers 

 on the fubject, though I have reafon to think it not uncom- 

 mon. The waters of Aftrop, near Banbury, contain car- 

 bonat of lime diflblved by the carbonic acid : and, when 

 the carbonat has been feparated, by boiling the water, the 

 fame appearance is produced by fulphate of argill. Its 

 origin, and that of the decbmpofiticn of the mercurial fait, 

 will be fhewn in the fequel. 



IV. THE METALLIC SALTS. 



Several phenomena demonftrate the exigence of fome 

 metallic fubflance in this water, befides the precipitate 

 already defcribed (11.) : but it is fo peculiarly combined, or 

 otherwife modified, as to^elude, in a great meafure, the 

 action of the ordinary re-agents. When the water is boiled 

 in contact with fome of the metals, it becomes turbid ; arid 

 the metal is partly oxydated, and partly dhTolved. The iron, 

 which has been ufed in the conflruclion of the baths, is 

 almoft destroyed : the tin, which lined a veflel ufed as a 

 warm bath for children, has fullered in like manner. If the 

 water be only boiled and poured into a wine-glafs with a 

 bright key in it, the liquor becomes turbid before it is cold. 

 Copper feems to refill its acYion better ; but this is only in 

 a low temperature ; for, if the water be boiled in a copper 



Vol.. I. S veflel. 



