Evening star. [volume] (Washington, D.C.) 1854-1972, 1881-12-21
KEEPING WARM.
Some Scientific Facts and PRINCIPLES.
Plainly Stated, with Practical Les
sons they Teach.


From the American Agricultural.
During January and February over most of
this country and the whole northern hemisphere.
a large proportion of the time. effort. and ex-
pense of all classes is devoted to keeping warm
"a much larger proportion than one would sup
pose without some thought on the subject.
Fuel is only one item; f0urfold clothing and
bedding as compared with summer, warmer
dwellings and largely increased food supplies
are to be reckoned in. There are some scientific
principles involved. SO simple that all NAV COM
prehend them, an understanding of which will
be or practical advantage. They apply to all
warm-bioeded land animals, man included.
$50.
The bodies of all human beings are so consti-
tuted that while some parts may be temporarily
benumbed with cold without danger, the blood
that circulates through the heart and through
the system generally. must be maintained uni
fOrnly at just about 9S15so of temperature $751; e
Fahrenheit, or 370 centigrade). If the heat of
the blood rises or falls only or Z degrees from
this normal point and continues so. fatal results
are expected. Every degree that disease ele-
Yates the general internal heat above 1909 is
a rapid approach towards the danger point. and
when only 1852 is reached, the most skillfui eff
forts OF physicians are usually needed to save
lie. On the contrary, even in the coolest reg
ions where the thermometer marks CO., or no
or more below the freezing point. the internal
neat must be kept up. and if it falls only from
$50 to $40 or $50, and continues thus. there
is great danger that the wheels of life will
stop. (These are general statements, appica-
BILE to a healthy condition. Cases have
been reported where in tetanus or lOckiaw
the temperature rose to nearly lilo, while
in asthma it sunk to 7So, and in cholera to Sc.
DEVELOPING HEAT
The natural process of maintaining the uni
formity OF blood temperature is a most interest
ing study, of decided practical utility to every
one. Whatever the nature of heat. it's relations
TO electricity. to mechanical and chemical force.
its various methods of production or exhibition.
etc. we all know some of it's effects, and some
methods of securingits manifestation Wekn0w
it may apparently exist in an invisible or inactive
form that in a cold room with cold wood or coal
and cold matches We can develop intense heat:
that ice water poured upon ice cold unslacked
lime will produce scalding temperature; that
beating cold iron with a cold hammer will sensi-
bly, warm it; that simply rubbing two cold pieces
of wood together makes them hot; that eectri-
city from a cold battery sent through a fine wire
or film of charcoal will produce the intense
heat that gives the electric light. So chemical
or mechanical, or electrical action, develops
neat that was before latent. or insensible or
that existed in another form.
hoW HEAT Is DlffCSED.
We know also that heat is ,'udsoted, that is. II
flies out in straight lines, as from fire or the
sun; we can feel the heat strike u.s. These heat
rays can be bent like light rays, by interposins
rejecting surface in their path to change then
direction.
Heat is also carried as freight, so to speak. as
when air takes 1t from stove and carries it TO
the top of rOOm or from hearth fire ont O1
the chimney; or when water particles carry If
from the bottom to the top Of kettle set over
the fire. go WA
Heat is also conducted or passed along from
one body to another. and also from one particle
10 another in the same substance. Hold one
END or side of piece of metal to fire. and the
nearest PARTICLES of metal will take in heat. and
pass IL TO the next PARTICLES and these to the
next, ana SO on until the heat is conducted a
loiig distance. But experience and experi.
Ihents snow that different substances differ
very greatly In their ability Ito thus conduct
heat through them This Is matter OF
much practical Importance as we shall see.
iron, Tor example conducts heat freely and rap
ldiy through itself; wood and glass feebly and
slowly. AR conducts ues.y title heat through its
substance, though it allows rd1fidted heat Gin
straight iines) to pass freely; and IL the air par
ticies are free to move they carry heat from
one point to another, usually upward, but hori-
zontally when moving thus as in wind cur
rents.
HOW HEAT rs PRODUCED.
The external, artificial heat used for MAIN
tanning the warmth of our bodies, beyond what
comes from the sun, or from air currents. is
mainly derived from chemical action in burn
ing wood or coal One-ffth ofair (of its weight)
is gas called oxygen. Nine-tenths of water
Ia oxygen. In the air the Oyvron Ia