Evening star. [volume] (Washington, D.C.) 1854-1972, 1911-02-12
For a Cold or Hot Day

| HAVE YOU never wondered on some terri
IL bly, cold winter day. when the falling
temperature had long since passed the zero
mark, if il could possibly be any colder any
where: and then. when summer comes and
| the mercury Is apparently never going to
stop climbing, YOU cannot imagine how any
| thing could be hotter or more uncomfortable?
Fortunately. we live in world where the
temperature seldom exceeds the limits of say,
| fifty degrees below zero Fahrenheit), and one
hundred and ten above. This seems a ire
mendous range of temperature; but it is on
| " trivial compared with that found on every
side in Nature or in the laboratory. Why,
this one hundred and sixty degrees is less
| than the range through which dish of cold
water is heated when you place it on the
| stove to boil.
| higher and lower temperatures is well worth
while Liquid air at three hundred and
twelve degrees below zero is cold; but liquid
hydrogen at four hundred and twentyone
is still colder, while liquid helium at four
hundred and fiftv-one below zero is the cold
est thing we know of. Going the other way,
lead melts at six hundred and twenty de-
grees above zero Fahrenheit), while gold re-
mains solid up to a bright red heat, or nine
teen hundred and forty-six degrees. A good
furnace fire may get several hundred degrees
hotter than this Platinum, one of the most
refractory metals melts only when intensely
white hot at a temperature of thlrty-tWo
| hundred and thirty; but even this is a hun
dred degrees SO less than the temperature
of the flame on your gas stove.
The hotter q BODY * the more light 1T
gives; SO the tungsten lamp filament, which
| runs at about forty-tivc hundred degrees,
gives a brighter and winter light than the
carbon filament at thirty-five hundred. The
electric arc gives still more light for a given
amount of current consumed, and generates
| temperature not far from seventy-two hun
bred degrees (Fa.lrenheit. This is the highest
temperature we can produce art1flclally. No
metal known can stand this terrible heat,
| and even most refractory substances, such
| as carbon, are volatillzed by it.
But. while the arc is indeed hot, it is by
no means the highest temperature to be
found in Nature. There are the best of rea-
sons for believing that the temperature of
the sun is some twelve thousand degrees or
| more, and it is probable that some of the
stars are still hotter. This great heat ex-
plains the almost unbelievable fact, found
by Langley, that sunlight is five thousand
times brighter than the dazzling stream of
molten metal from Bessemer converter.
L. I. Rose
Absorb Heat
a y interesting instance OF the application
= on a large scale of the principle that
black colored substances readily absorb the
heat of the sun, is seen in the case of toll
road in California.
This toll road from Truckee to Lake Ia
hoe is closed early every winter by the inn
mense snowfall. which in places is twenty to
thirty feet deep. At the beginning of spring
the owner of the line has black dirt scattered
along the surface of the snow where he
knows that his hidden road runs The layer
of dirt is not made SO thick as to cut off the
| sunlight from the snow completely. The
effect is described as wonderful. In short
| time a long depression is formed in the snow,
and days before the ground is clear on either
side stages are running on bare ground.
Divers Heats
TO the ordinary laynan heat is heat with
no variation save in intensity. Yet
science says that several varieties OF heat
exist and starts in to prove it. What will
heat one thing will not heat another, while
some things are susceptible to nearly all
kinds.
Take glass lens and focus the light from
an electric arc upon an air thermometer
several feet away. An air thermometer is
made of glass and air and tells ordinary
temperatures as we'll as any kind. 1t will be
found, however, that this beam of light has
1 nfTa 4 +Io c1,,lt