. 
PHYSICAL anv LITERARY. 175 
which the faline purges commonly ufed 
are not obferved to do. But there feems 
at leaft to be no objeCtion to its ufe when 
children are troubled with an acid in their 
ftomach; for gentle purging in this cafe 
is very proper, and it is often more con- 
- veniently procured by means of magnefia 
than of any other medicine, on account 
ef its being intirely infipid. 
THE above mentioned author obfer- 
ving, fome time after, that a bitter faline 
liquor, fimilar to that obtained from the 
brine of falt-petre, was likewife produced 
by the evaporation of thofe waters which 
contain common falt, had the curiofity to 
try if this would alfo yielda maznefia, The 
experiment fucceeded : And he thus found 
eut another procefs for obtaining this 
powder, and at the fame time affured 
himfelf by experiments, that the product 
from both was exadlly the fame*. 
My curiofity led me fome time ago to 
inquire more particularly into the nature 
of magncfia, and efpecially to compare its 
L pro- 
, ® Hoff, Op. T. 4. p. 500% 
