The Ottawa free trader. [volume] (Ottawa, Ill.) 1843-1916, 1859-11-05
The CuriosIiies of The sunbeam.


Simple as a white ray Of the suns light
appears, it is found, ON close observation
TO be composed of VI least three distinct
elements, and to possess many curious and
wonderful properties. The three elements
of which we speak, are light. heat and
chemical force; aad they may be separa-
ted from each other by means of very
simple instrument Darken room and
bore Il small hole through one Of the win
GOw-shuttcrs, so as to aClIait ray OF light
from the sun Place triangular prism Of
glass across the ray, with one edge down
so that the light may pass through it
The ray viii be bent upward, and Will
strike the wall ut a higher point than it
did before the prism was interposed. 1t
will not, however, all be bent equally, so
as 10 make the round spot it did before.
but VIII form an elongated image Of seven
brilliant and most delicate colors, which
shade into each ether and fade away in
definitely ut the ends of the image. The
lowest OF these coiors, when the prism Is
placed as directed, is always red and the
others, III order as we ascend, are orange,
yellow, green, blue, indigo and violet
Suspend a delicate thermometer in each of
the coiored rays, and it will be found that
the violet ray imparts the least heat, and
through the several colors If we contin-
ue our observations with the thermometer
down beyond the red ray, we find a point,
where no light falls, where the thermome-
ter receives more heat than it does any
where within the light. The rays of light
are separated by the prism from those of
| heat.
Another curious fact which has been OBJ
served also proves that the light and heat
of the sunbeam are distinct elements. If
we suspend a thermometer in the vicinity
of close stove, which emits heat but not
light, the heat radiating from the stove
will raise the mercury in the thermometer.
But if we interpose plate of transparent
! glass, none of these dark rays of heat pass
through it; it is entirely opaque to them.
If we now increase the temperature of the
stove until it becomes red hot, the rays of
4 heat begin TO pass through the glass and
affect the thermometer; and if we raise
the temperature to a white heat, the rays
pass freely through the glass. If we vary
the experiment, and use crystals of rock
salt, instead Of glass, we find that the dark
rays OF heat pass out as freely through the
salt as those which are accompanied with
Light.
Some Of the alchemists discovered. cen
turtles age, 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 large number of
| bodies are thus affected by light 1t is
| this power of light which is used in the
daguerreotype and photograph processes.
By more than one means, the force of this
element can be measured i'll the several
parts of the spectrum and it is found to
be most powerful in the violet ray, and to
extend entirely beyond the light it is
not visible TO the eye; it does not affect
the thermometer; and it is therefore nei-
Their light nor heat. 1t is easy, after thus
dividing the sunbeam, to re-combine its
parts, when the white ray will produce the
several effects of light, of heat, and of
chemical change, which are produced sep
arately by its several elements.-,Seientitc
american