of Magnefian Earth. 471 
have known the quantity required for the 
folution of the latter. 1 have found twenty 
grains of mild Magnefia require an ounce and 
half of diftilled vinegar for its folution. This 
may feem a large quantity ; but let it be re¬ 
membered that, “ the quantity of each balls, 
** requifite to faturate a given quantity of each 
<e acid, is, dire&ly as the affinity of luch acid 
<e to each balls.”* 10© grains of real vitriolic 
acid require 215 of vegetable fixed alkali 
to neutralife them; whereas the fame portion 
of acid would be neutralifed by 80 grains of 
Magnefia; and the proportional quantity of this 
earth to that of the alkali, necelfary to faturate a 
given quantity of acetous acid, would be Hill 
fmaller. 
But Mr. Kirwan’s experiments are more worthy 
of attention. His accuracy in every thing he 
undertakes is undeniable; nor would he pro¬ 
bably have erred, but in a cafe in which the 
mod faithful Experimental!!! might be liable 
to deception. 
I do not know any thing more fubjedl to 
variety than the folubility of pure Magnefia 
in acids. I have dilfolved 1 1 grains of aerated 
Magnefia in fufficient quantities of each of 
the four principal acids, when I have found the 
earth neutralifed. Five grains of pure Magnefia, 
which is equal to twelve of the aerated has 
* Kirwan in Phil. Tranf. vol. LXXIIf. p. 38. 
H 4 dlffolved) 
