102 4n ANALYSIS of 
vitriolic acid, compared with that of water, was as 1798 to 000, 
in a temperature of heat equal to 60 of FAHRENHE!T. When 
I had ufed it on former occafions, I diluted fome of it, with 
four times its weight of diftilled water, and ufed this mixture 
in place of the pure acid, that | might the more readily portion 
it into fmall dozes ; but on this occafion, 1 made a mixture of 
it, with about roo times its weight of diftilled water; and ef- 
faying this mixture afterwards, with great attention, I found 
that 112 grains of it faturated one grain of the pure alkaline 
part of the alkali of tartar, and 171.55 grains were required 
for the faturation of one grain of the pure or cauftic part of the 
foffil alkali. 
Wiru this largely diluted acid, the ftrength of which was 
thus afcertained, I began to inveftigate the quantity of alkali 
in the Iceland waters. 1 gave a pale purple or blue colour to a 
portion of the Rykum water, by adding a few drops of an in- 
fufion of litmus, the bluifh purple of which became more 
blue when mixed with this alkaline water, and I began to add 
very gradually fome of the largely diluted vitriolic acid, ex- 
pecting to fee the colour change to a reddifh purple, when the 
alkali became completely faturated. ‘This method, however, 
did not fucceed fo well as I had fuppofed; for although I 
changed the colour to a reddifh purple, or even to a pure red, 
by adding an exceeding fmall quantity of the diluted acid, the 
red thus produced was not permanent. Next day, I found it 
returned again to the blue, and requiring a new addition of 
acid; and this happened fo often, after repeated additions of. 
acid, that this procefs appeared very tedious, and fcarcely ca- 
pable of being brought to a precife limit ; for in proportion as 
I continued the procefs the longer time, or had made the more 
numerous additions of acid, the time neceflary for the return of 
the colour from red to blue was always* the longer, and at laft 
was no lefs than feveral weeks. 
THESE 
