i. er 
ane eo ee 
ARSE ag 
es lan bos. 
. 
5 i 
= , 
WATERS from ICELAND.. 113 
of the glafs, and the upper furface of whieh was level and 
‘fmooth. I knew the quantity of filiceous earth contained in it ; 
and comparing this with the weight of the water, when reduced 
by boiling to gr. 138, I found the proportion of the earth to 
that quantity of water to be as 2.68 to 1000; and having 
weighed the jelly by itfelf, the proportion of filiceous earth to 
the water in it, fappofing that it contained the whole of the 
earth, was 10.88 to rooo. In another experiment, in which 
a fimilar mixture had been lefs boiled, and in which the filice- 
ous earth bore to the water the proportion of 2.1 or 2.2°to 1000, 
I found a foft jelly formed at the end of forty days. And in 
another, in which the boiling and evaporation was continued 
until the jelly began to be formed in the upper part of the li- 
quor while it was boiling, I found the proportion of the filice- 
ous earth to the remaining water to be nearly as 3.75 to 1000. 
Arter this jelly is once formed, I never could bring it again 
into a ftate of diffolution by water alone, whatever quantity of 
this laft was added. 
Ir appears therefore by thefe experiments, that when filiceous 
earth, united with an alkali, is diffolved in 1000 times, or in 
more than 500 times its weight of water, it will not feparate or 
fubfide from that quantity of water, although we feparate or 
difengage the alkali from it. The particles of it, placed at that 
’.diftance, do not aét on one another by their attraction of cohe- 
fion or concretion. It is neceffary, in order to enable them to 
attract one another, that they be brought nearer, by diminith- 
ing the quantity of the water, until it be lefs than 500 times 
the weight of the earth. When this is done. they will enter 
into a ftate of cohefion, fooner or later, according as the water 
‘has been more or lefs diminifhed. But this {tate of cohefion 
into which they firft enter, is alfo remarkable. The force of it 
is exceedingly weak, and it takes place while the particles of 
the earth are ftill at a confiderable diftance from one another. 
They therefore retain and entangle among them a large quan- 
Wo... HI, P tity 
