Evening star. [volume] (Washington, D.C.) 1854-1972, 1881-12-21

substance (nydrOgen) which il win not readily
leave. So while the free oxygen of the air in
creases fire, the oxygen is tied up in the water
ana water extinguishes q fire by shutting out
| free air oxygen.
Coal, hard or soft is mainly a substance called
CARBON. Diamonds are pure carbon in crystal
| lorm. Almost all substances that grow in plant
form, and all kinds of flesh are largely made up
| OF TINS carbon. FIVE put under cover Ito shut
OUT arr wood. straw, grain. -four. vegetables
| fruits or any kind of flesh, as lean or fat meat
| or almost anything used for food and apply
strong heat, we drive Off good deal of water
| In the form of vapOr, and little of some other
| substances, and we have mass of nearly pure
carbon or charcoal left-in bulk usually as large
as the original substance heated. This is seen
| IN changing wood into charcoal under a cover
| ing of earth, where little air is admitted AFT the
] bottom to burn Just enough of the wood to heat
| or char the rest. The same would happen to
| masses OF our common food put in place of
| part OF the wood. II we admit too much air
the charcoal itself will disappear. Charcoal
gives hotter fire than wood because this pre-
| lImlnary heating has removed the other sub
| stances that in turning to vapor and gases alb
| Sorb and carry Off a great deal of heat.
SOME PROPERTIES OF HEAT.
| Other preliminary items, Sensible or active
| heat seems to combine with some substances
and disappear. If the air in room should sud
| denly expand to fill two rooms some heat would
disappear and the expanded air would feel
| much colder. If we cOndense the air suddenly
| into much smaller space it will give up heat
| that was before inscnsible. If We put piece of
| finder in the closed end of gun barrel. and
with close-ftting ram-r0d quickly condt7,se the
| air upon the finder, it will give out so much
heat a to set the finder on fire
| Ii one pint of water be changed to hot or cold
vapor the vapOr will take up and conceal
nearly LOCO degrees of heat, or heat enough
to Sop raise 81 pints Of water from freezing
| (S2') to boiling (2l2o) or this heat was
| not concealed, or did not disappear. the
| clouds. which are cold vapor. would be much
hotter than melted lead) This heat is SINH
| larry concealed, whether the water turns into
visible steam at 2l2 deg, or passes off as cold
a'oss,oR Vapor in the air. or in the ristbe vallor
of fogs and clouds The point is. that the evap-
Grafton OF water, hot or cold, invariably pro-
duces lower temperature 10y concealing and
carrying away great amount Of heat.
we can keep water, milk ETC. cool and
| render them colder. by wrapping the jug pitcher
! or other containing vessel with cloth and keep
| ing this moistened. The evaporation going on
carries off neat. If the vessel be thin porcelain
or eartben ware or metal, the heat will pass out
wardly to the cooperating surface more
readily. Damp or wet clothing. for the same
| reason. quickly cOOls the body and produces
chiiliness. and is very likely to induce a cold,
especially if not uniformly damp.
One point more. When air is warmed. it has
tne power OF holding concealed an increased
amount of nate. in the form of invisible vapor
and when cooled it gives ont this water again
I'D visible form There is frequently more
water in the air above hot clear sum-
mer day, than on other dark. cloudy, or rainy
ones. In the latter case cold air wave or
some other cause, has reduced the temperature
OF the air above us; it has less capacity for con-
ceaied moisture. and gives it up: the moisture
thus set at liberty cOndenses into visible clouds,
and If the uniting of these little gObues be con-
tlnued they become too heavy to float in the
| air and fall as rain drops Heating the air in
| room makes it hide water; it becomes hungry
| for more and extracts it from the skin and from
our lungs; we feel parciled and disagreeable.
Lesson: Always keep plenty Of evaporating
water surface in any and every room warmed by
! stove, furnace, or in any way.
FIRE IN THE BLOOD.
When the oxygen of the air unites with the
carbon of hard coal or charcoal or of wood OF
of -four meat, or of any other food compound
is formed, viz. gas, which we call carbonic
acid. The process of forming this compound
sets at liberty heat which was before entirely
concealed or which existed in another form and
when coal or wood is burned rapidly We have a
hot fire. The same process goes on when wood
rOts away. but the heat is developed SO slowly
that we do not notice it.
precisely the same thing is taking place in Hte
human body all the time. The food We eat and
digest. is in pant absorbed into the blood and
carried by it everywhere throughout the body
But at the same time the blood passing through
the lungs is constantly picking up oxygen there
from the air which we breathe into the lungs
and this. too. goes all through the body and at
millions OF points one carbon atom of the food is
uniting with two atoms of oxygen from the air.
forming carbonic acid and setting heat n: itbf7fy
precisely the same as takes place in burning
wood OF coal in the stove. There is only a
small product of heat at any one point in the
| blood. but 1t takes place at so many points that
there are enough developed to keep up the gen-
eral temperature AND a wonderful provision
it is, that without our supervision or knowledge
even, this ever burning fire goes within us.
Just SO as to keep the whole body at about 80
deg. eve speak only of the main source of
animal heat. There are other combinations
going on in the body. which produce more or
less heat. such as the union of hydrogen from
food with oxygen, which escapes as water: the
union of minute quantities of sulphur and of
phosphorus with oxygen. etc. Most probably
more or less heat is also derived from the me-
| chanical movements of the various organs.)
If the supply of food fails in the blood for q
time, from fasting or sickness then the oxygen
in the blood attacks any stored up fuel as fat.
flesh. and other organs of the body. using their
carbon to keep up the yer necessary warmth
The weight of the body grows less and when
no more fat or flesh can be found to make heat.
cold and death come on. The same result fol-
lows if the lungs become so diseased as not to
furnish the air supplying oxygen fast enough to
keep up the internal fire. Stop the entrance of
air for few minutes by closing the windpipe
with cord, or by filling the lungs with water
and heat production stops in the blood. the
temperature falls below 93o and the human
| machinery ceases to work.
The carbonic acid produced is poisonous In
the stove it escapes through the pipe That
| formed in the blood is carried to the lungs and
| thrown out into the air. Too many persons
breathing in close room fill it with so much
| carbonic acid that it becomes very unhealthful
if not dangerous.
The blood carries the heat to the surface of
| the body. as well as to all other parts, and a
good deal of heat escapes off into the air. 1.-THE
air is cold this escape is more rapid, and more
heat must be produced within to supply the
waste. That means more fuel, that is more
| food. or more flesh is consumed Remember
that the blood must be kept up to So. of
course then. in cold weather more food is neces-
sary Or the body becomes emaciated. But any
thing that stops escape of heat from the surface
OF the body. saves food or saves using up flesh
Warm clothing, warm air. warm dwellings,
warm stables. warm sheds, all help to stop this
waste OF heat.
FURTHER PRACTICAL LESSONS
AS to domestic animals is not the above a
positive proof, that sheltering all animals from
cold weather, from chilling winds which by their