180 ESSAYS anp OBSERVATIONS. 
tral falt of magnefia and diftilled vinegar; 
chufing this acid as being, like that in 
weak ftomachs, the product of fermenta- 
tion. Six drams of this I diffolved in wa- 
ter, and gave to a middle-aged man, de- 
fring him to take it by degrees, After 
having taken about a third, he defifted, 
and purged four times in an eafy and gen- 
tle manner. A woman of a {trong con= 
{titution got the remainder as a brifk pur- 
gative, and it operated ten times without 
caufing any uneafinefs, The tafte of this 
falt is not difagreeable, and it appears to 
be rather of the cooling than of the acrid 
kind. 
Havine thus given a fhort fketch of 
the hiftory and medical virtues of mague- 
fia, 1 now proceed to an account of its 
chemical properties. By my firft experix, q 
ments, {intended to learn what fort of neu- 
tral falts might be obtained by joining it 
to each of the vulgar acids; and the re- 
fult was as follows. 
MacGNeEsia is quickly diffolved with 
violent effervefcence, or explofion of air, © 
_ by the acids of vitriol, nitre, and of com-_ 
mon 
