J 9 ° Continuation of the Experiments and Ohfervations 
of the cryftallized fait contain 28,8 of acid, 50,09 of alkali, 
and 2 1, 1 1 of water. 
Or mere marine acid, 100 gr. of this alkali required from 63 
to 66 or l j gr. ; perhaps one reafon of this variery is, that it is 
exceeding hard to hit the true point of faturation. Allowing it 
to be 06 gr. then 100 gr.. of perfectly dry common fait contain 
iieaily 55 of real acid, C3 of alkali, and 15 of water; but 
100 gr. ot the cryftallized ialt lofe 5 by evaporation ; then 100 
gr. of thefe cryftals contain 53,3 of acid, 50 of alkali, and 
16,7 of water. 
^ he proportion of fixed air, alkali, and water, in cryftal- 
lizec mineral alkali, I mvefligated thus : 200 gr. of thefe cry- 
flals were diffolved in 240 of water ; the folution wasfaturated 
by fuch a quantity of fpirit of nitre as contained 40 of mere 
-nitrous acid.; hence I inferred, that thefe 200 gr. of alkali 
contained 70 of real alkali. The faturate folution weighed 
40 gr. lefs than the fum of its original weight, and that of the 
fpirit of nitre added to it; therefore it loft 40 gr. of fixed air. 
1 he remainder, therefore, of the original weight of the cry- 
ftals muft have been water, that is, 90 gr. ; confequently 100 
gr. of thefe cryftals contained 35 of alkali, 20 of fixed air, 
and 45 of water. 
Ihis proportion is, particularly with regard to the alkali, 
veiy different fiom that found by Mr. bergman and Lavoi- 
sier, which I impute to their having ufed foda recently cry- 
ftallized. Mine had been made fome months, and probably 
loft much water and fixed air by evaporation, which altered 
(the pioportion of the whole. According to the calculation of 
thele philolophers 100 gr. of this alkali takes up 80 of fixed 
air. 
The 
