Idaho County free press. [volume] (Grangeville, Idaho Territory) 1886-current, 1889-02-08
AN INTERESTING STUDY.
A Semi-Scientifc Illustration Showing
Why Water Puts Out Fbe.

nave Often been puzzled To answer
for myself why water extingulshes
fire. A great many people say it is
because the water and it's steam SO en-
velop the burning material as to ex-
clude the oxygen, and thus the fire
must stop. This seems to be an ineffi-
cient, if not an entirely erroneous
reason. My reason is this: We know
that nothing will burn q. e., unite
with oxygen with the evolution of
heat and Light unless and until it has
been raised to a given temperature
Thus: Sodium burns at ordinary tenn
perature-abo sixty degrees if dry
the gas of ordinary kerosene at about
ITO degrees or less, and so on. Why
do we tip piece of stick with sulphur
and then with phosphorus to make
matchesp Because, while wood must
have quite a high temperature, phos-
phorus will burn at comparatively
low mperature-so low that the heat
developed by slight friction will ignite
it. The phosphorus makes heat
enough to ignite the sulphur, but not
enough to start the wood. But | will
ask another questions: Wood ashes are
white. Why is the remaining end Of
the match and often most of it black in
colorP Is it not because carbon being
black, and the wood being composed
of carbon and compound substances,
which are very infiammable. The lat
ter burn, but do not generate enough
heat to OXidize the formerp This
seems to me the reason for the carbon
remaining. Thus promising, and
showing. that carbon which forms the
bulk of wood Gas we'll as of paper,
cotton, etc. requires to be very hot
before it will unite with the oxygen,
we may consider the water for a mo-
ment.
Perhaps the easiest way to make my
point clear is to take common illus
tration. Every one knows that if one
puts kettle of water on heated stove
he must wait long time for it to be-
come boiling hot, or a temperature of
PIP degrees f. Now, II he should put
the same amount of quicksilver on by
the side of the water, the latter would
reach PIP degrees far sooner. Why is
this? 1t is because the water takes up
large amount of heat which is there
in the water, but which the ther-
mometer does not index. Now, if
after reaching PIP degrees, he sets
them off, the mercury will reach the
temperature of the surrounding air
much more rapidly. Now, sup
pose we wish to boil all the water
away, to evaporate it, in that case re-
member that in passing from water to
steam the temperature is not raised
even degree, nor any fraction of one,
could he not make it all evaporate in
stantly by raising the temperature a
littleP We all know he could not; that
the fire has a degree of heat several
hundred degrees higher, but the kettle
must remain long time, while
the water very gradually goes off
as steam. Why SOP Because the
water, in becoming steam, must take
into itself a large amount of heat not
shown by the thermometer, and as
the heat can be added only gradually,
the formation of steam is slow. Now,
in the large amount of heat which
water can take up, and the fact that
ordinary inhammables must be raised
to high temperature in order to
burn, we have the cause of water put
ting out fire. Put burning match
into very small drop of water, and it
is extinguished, because of the very
large amount of heat taken from the
match in reducing the water to steam,
which renders the temperature of the
match too far below PIP degrees, or at
least that far If there is water enough.
and so the carbon and its compounds
forming the wood will no longer unite
with the oxygen of the air. For the
same reason, a hot iron thrust into the
water is cooled, and water sprinkled
on the floor cools the air, the heat of
evaporation in the latter case coming
from the air itself, thus cooling it.
Now, if we could find fluid very
plentiful, which requires more heat
than water to make it boil, evidently
we could put large fires out much more
readily.--B. B. James, IN Trade man.