106 An ANALYSIS of 
place, be deducted from the gr. 91.68, and thus we have 
gr. 88.18, as the quantity of the diluted vitriolic acid which 
was employed folely in faturating the alkali of the water. But 
from the effays I had made of the power of this diluted acid in 
faturating alkalis, it is evident that this quantity of it was fuf- 
ficient for faturating gr. 0.514 of the pure or cauttic foflil alkali, 
or gr. 0.857 of that which is faturated with air and evaporated 
to drynefs, or about gr. 2.38 of that which is faturated with 
air and in form of tranfparent cryftals. 
Tue next ftep was to make a fimilar experiment to determine 
the proportion of alkali in the Geyzer water ; but here I found 
it neceflary to change a little the mode of afcertaining the point 
of faturation.. 
Tue water of Geyzer, by means of the fulphureous gas, 
which it contained in greater quantity than the other, and per- 
haps alfo by means of fome of the other ingredients which it 
contained, and which gave it a light yellowifh colour, pro- 
duced fuch a change in the colour of litmus, that it could not 
be employed, as in the laft experiment, by mixing it with the 
acidulated water and boiling them together; the purple of the 
litmus was changed to an orange, which could not be made to 
return to blue or purple, although J added a quantity of alkali, 
which rendered the liquor very evidently alkaline, when it was 
examined by other trials. I therefore had recourfe to the com- 
mon method, which I had formerly praétifed in many other 
experiments of a fimilar nature, I mean the ufe of linen rags, 
or bits of cambric, which had been tinged with an infufion of - 
litmus. A little bit of thefe, when touched with a liquor that 
is in the fmalleft degree acid or alkaline, has its colour changed 
from the purple to red or blue. ‘This method is, next after the 
one employed in the laft experiment, the moft nice that 1 know; 
provided that, in having recourfe to it, we remember what was _ 
remarked in the former experiment, that the litmus colour is 
affected by acids in general much more eafily than by alkalis ; 
and 
