The Cecil Whig. [volume] (Elkton, Md.) 1841-current, 1862-01-11
CuriOsities of the Sunbeam.

Simple as the white ray of the suns light
appears, it is found, on close observation, to
be composed Of at least three distinct ele-
mcnts, ana to possess many curious and
wonderful properties. The three elements
OF which we speak, are light, heat, and chem
ical force ; and they may be separated from
each other by means of a simple instrument
Darker room, and bore a small hole through
one Of the window shutters, so as to admit Il
ray of light from the sun. Place triangular
prism of glass horizontally across the ray
with one edge down, so that the light may
pass through it. The ray will be bent upward
and will strike the wall at a higher point than
it did before the prism was interposcd. 1t
will not, however, all be bent eqna!ly, so as
to make the round spot it did before, but will
form an elongated image of seven brilliant
and most delicate colors, which shade into
each other, and fade away indefinitely at the
ends of the image. The lowest of these
colors, when the prism is placed as directed,
is always red and the others, in the order
as we ascend, are orange, yellow, green, blue,
indigo, and violet. Suspend delicate Their
mometer, in each of the colored rays, and it
will be found that the violet ray imparts the
least heat, and that the heat increases as we
pass down through the several colUrs. II we
continue our observations, with the thermom-
eter down beyond the red ray, we find point
where no light falls, where the thermometer
receives more heat than it does within the
light. The rays of light are separated by the
prism from those of heat
Another curious fact which has been
observed also proves that the light and heat
of the sunbeam are distinct elements. Ii we
suspend q thermometer in the vicinity of a
close stove which emis heat but not light,
the heat radiating from the stove will raise
the mercury in the thermometer. But if we
lntcrpose plate of transparent glass, none of
these dark rays Of heat can pass through it
1t is entirely opaque to them.
If we now increase the temperature of the
stove until it becomes red hot, the rays of
heat begin to pass through the glass and
affect the thermometer; and if we raise the
temperature to white heat, the rays pass
through the glass. five vary the experiment,
and use crystals OF rock salt, instead Of glass,
weifind that the dark rays OF heat pass out as
freely through the salt as do those which are
accompanied with light.
Some Of the alchemists discovered, CEN
turtles ago, that the chloride of silver, which
is as white as snow, turns black on exposure
to the light; and more recently it has been
found that a large number of bodies are thus
affected by light. 1t is this power of light
which is used in the daguerreotype and pho
iosIaPh Ploccss. by inorc thah oue HcaNS,
the force OF this element can he measured in
the several parts of the spectrum, and it is
found to be most powerful in violet ray, and
TO extend entirely beyond the light. 1t Is
not visible to the eye; and it is therefore
neither light nor heat. 1t is easy, after thus
dividing the sunbeam. to recombine its parts,
when the white ray will produce the several
effects of hight, of heat, and of chemical
change, WHICH are produced separately by
its several elements Scientific american.