', Vj ‘''ti
1112O: water,' after the niceft mechanical
divifion. It is well known that the
diifolubility o f any fubftance may be
Icilened by certain compofitions ; and
that a folvent can better attack the
fubftance, according to the extent o f
its iurface ; and laftly, that water in
an open veiTel will not admit o f any
greater degree o f heat than one
hundred degrees, according to the
Swedifli thermometer. A fubftance
may, by this rule, be diiToluble by
itfelf, after having gone through a
preparatory cleanfing, or a chemical
reparation, or with the aififtance o f a
greater degree of heat, though it might
be indiiToluble without any preparation,
or with the ufual method o f boiling
; and it is ivith a view to this cir-
cumftance that I call the flint a kind
o f fait earth.
I have likewife examined the fub*
ftances you colleéled in the morafs
near the Geyfer, and have found them
to be the following :
3. A dark-red bole, which became
darker in the fire, but was afterwards
a little attracted by the magnet. It
crumcrumbles
into pieces in the water, and
is fine and tough to the touch.
4. A bluifli-grey clay, which contains
green vitriol o f decayed pyritse.
5. A brighter grey fort, which did
not feem to contain any vitriol.
6. A white or yellowiili clay, with
ruit-ipots.
All thefe forts become very hard in
the fire, and take a good deal o f time
before they liquefy. The laft, when it
foftens, is more harfli and Tandy to the
touch than the preceding forts.
The different forts o f ftone colle(fted
at Laugarnas are o f another nature :
nor does the water here fpout out o f a
baibn, but through many fmall openings
in the earth.
7. A whitifli irregular plated cruft,
which often grows on the outftde into
fmall globular blunt points. This in
acids gives a fndden fermentation,
that immediately ceafes without its
being any otherwife attacked. It
diflblves with borax by the blow-pipe
with great diiflculty, and without
motion, but with a loud eftervefcencc
with