The Princeton union., 1881-05-12
FORMATION OF CLOUDS.

FORMATION OF CLOUDS.
Interesting Facts in PHYSICAL Science.
Whence comes the rain which forms
the mountain streams? Observation
enables you to answer the question.
Rain does not come from a clear sky.
IT comes from clouds. But what are
clouds Is there nothing you are ac-
quainted with which they resemble? ?
You discover at once likeness between
them and the condensed steam Of a loco
motive. At every puff Of the engine q
cloud Is projected into the air. Watch
the cloud sharply; you notice that it
first forms at little distance from the
top OF the funnel. Give close attention.
and you will sometimes see perfectly
clear space between the funnel and the
cloud. Through that clear space the
thing which makes the cloud must pass.
What, then, is this thing which at one
moment is transparent and invisible and
the next moment visible as dense,
opaque cloud?
1t IS the steam or vapor OF water from
the boiler. Within the boiler this steam
is transparent and invisible but to
keep it in this invisible state a heat
would be required as great as that with
IN the boiler. When the vapor mingles
with the cold air above the hot funnel it
ceases to be vapor. Every bit of steam
shrinks, when chilled, to much more
minute particle of water. The liquid
particles thus produced form kind of
water dust Of exceeding fneness, which
floats in the air. This is a cloud. Watch
the cloud banner from the funnel of a
locomotive; you see it growing gradual
" less dense. It finally melts away al
together; and, if you continue your OBJ
servations, you will not fail to notice
that the speed Of its disappearance de-
pends upon the character of the day.
In humid weather the cloud hangs long
and lazily in the air in dry weather It
is rapidly licked up. What has become
Of it? It has been reconverted into
true invisible vapor.
The drier the air, and the hotter the
air, the greater is the amount OF cloud
which can be thus dissolved in it. When
the cloud first forms, its quantity is far
greater than the air is able to maintain
in an invisible state. But as the cloud
mixes gradually with a larger mass of air
it is more and more dissolved, and finally
passes altogether from the condition OF
q finely divided liquid into that Of trans
parent vapor gas.
Make the lid of kettle air-tight. and
permit the steam to issue from the pipe;
cloud is precipitated in all respects
similar to that issuing from the funnel of
| the locomotive.
Permit the steam as it issues from the
pipe to pass through the flame of spir-
lt-lamp, the cloud is instantly dissolved
by the heat, and is not again precipi-
tated. With special boiler and special
nozzle, the experiment may be made
more striking, but not more instructive.
than with the kettle.
Look to your bedroom windows when
the weather is very cold outside; they
sometimes stream with water derived
from the condensation of the aqueous
vapor from your own lungs. The win
dows of railway carriages in winter show
this condensation in striking manner.
Pour cold water into dry drinking glass
on summers day; the outside surface
Of the glass becomes instantly dimm ed
by the precipitation of moisture. On a
warm day you notice no vapor in front
Of your mouth, but on a cold day you
form there little cloud derived from
the condensation Of the aqueous vapor
from the lungs.
You may notice in a ballroom that as
the door and windows are kept closed,
and the room remains hot, the air re-
mains clear but when the doors or win
dows are opened, dimness is visible,
caused by the precipitation to fog of the
aqueous vapor Of the ballroom. If the
weather be intensely cold, the entrance
of fresh air may even cause snow to fall.
This has been observed in Russian ball
rooms, and also in the subterranean
stables at Erzeroom, when the doors are
opened and the cold morning air is per-
mitted to enter.
Even on the driest day this vapor is
never absent from the atmosphere. The
vapor difused through the air Of a room
may be CONCEALED to hoar frost in your
presence. This is done by filling YES
sci with a mixture of pounded ice and
salt, which is condensed and freezes the
aqueous vapor. The surface Of the YES
sci is finally coated with frozen fur,
so thin that it may be scraped away and
| formed into SNOWFALL.
To produce the cloud, in the case of
the locomotive and the kettle, heat is
necessary. By heating the water, we
first convert it into steam, and then, by
chilling the steam, we convert it into
cloud. Is there any fire in nature which
produces the clouds of our atmosphere ?
There is, the fire of the sun.
Thus, by tracing backward without
any break in the chain of occurrences,
our river from its end to it's real begin.
nings, we come at length to the sun.
! Nicotine Poisoning.
A rather unusual case Of poisoning by
nicotine occurred in a Paris suburb,
The victim, a man in the prime Of life,
had been cleaning his pipe with clasp.
knife; with this he accidentally cut one
| e L. L