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PHYSICAL anv LITERARY. 239 
But if, on the other hand, a large propor- 
tion of the fedative falt be perfectly and 
fuddenly mixed with the alkali, the whole 
or a large pare of the air is as fuddealy 
expelled. 
In the fame manner may we alfo ex- 
plain a fimilar phenomenon, which often 
prefents itfelf in faturating an alkali with 
the different acids: The effervefcence is 
lefs confiderablz in the firft additions of 
acid, and becomes more violent as the 
mixture approaches the point of fatu- 
ration. This appears moft evidenily in 
making the fal diurcticus or regenerated 
tartar: The particles of the vegetable acid 
here employed being always . diffufed 
through a large quantity of water, are 
more gradually applied to thofe of the al- 
kali, and during. the firft additions are 
chiefly united to thofe that are freeft of 
air *. 
THAT the fixed alkali, in its ordinary / 
fiate, is feldom entirely faturated with air, 
feems 
 * Boerh. operat. chym. procefs. 76, 
