ee ea 
mination to be erroneous, as being different from the refult of the 
firft experiment, which is direct, and becaufe part of the acid 
efcapes in a ftrong heat. Different portions of a parcel of cry- 
ftallized mineral alkali, which had efflorefced by expofure to the 
air for fixteen months, afforded different portions of fixed air; 
yet without particular attention we may often be deceived, as 
the faturated alkali frequently reforbs a portion of the air it gives 
out, fo that the contents of air cannot be exaélly eftimated by 
weighing, unlefs the faturate liquor be fuffered to reft for fome 
hours expofed to the air. 
Mr. Wenzel having faturated 120 grs. of dry mild mineral 
alkali with his fpirit of vitriol, found the lofs ofair to be 
48 grs. the quantity of fpirit of vitriol expended 285,33 grs. 
the falt remaining after ignition 162 grs. or rather 161,5, a8 
% gr. of earth was precipitated, which muft be deducted from 
the alkali. Hence the quantity of pure alkali was 71,5, which 
deducted from 161,5, gives the quantity, as he thinks, of the 
ftrongeft acid =go grs. Hence it fhould follow, 
Tat 100 parts pure mineral alkali take up 125,87 of the 
ftrongeft acid, and afford 225,87 of dry Glauber’s falts. 
He elfewhere remarks that 240 grains of cryftallized Glau- 
ber lofe by ignition 134 grs. of water, confequently 106 
[=240—134] of the dried falt take up in cryftallizing 134 of 
water, then 161,5 of the dried falt fhould take up 204,16, and 
the fum of both is 365,66, the quantity of cryftallized falt pro- 
duced in the above experiment. 
Hence, 
