Evening star., 1899-04-14
THE SUNS HEAT.
We May Re Able to Cook With 1t in
the New Century.

From Pearsons Weekly.
Little by little man is mastering nature.
He has long taken advantage of the wind
with a mill and OF the flow or swift
streams or a waterfall with wheel. Then
the wonder of steam was brought to light,
and next electricity chained. And now at
last it seems he is about to utilize some OF
the vast forces that have been going 10
waste for ages. by causing waterfalls to
produce electricity which shall supply the
country for hundreds of miles with light
and power.
But the greatest of all natures forces
man has yet to cope with and TO master.
This is the sun. 1t is the source of all light
and heat, and as such it possesses the mar
velous power that would be sufficient to do
all mans labors if he could but discover
the secret and put it to practical use.
Scientists have realized this in the past,
and remarkable experiments have been
tried andsproduced most interesting results,
but, as might be expected, none that prom
ised practical or commercial success.
To go back to the very beginning of such
experiments, you viii perhaps recall the
story of Archimedes destroying fleet by
means of mirrors. The idea OF using the
suns heat you see, Is very Old; yet IN an
these centuries nothing practical has been
achieved.
1t is known that in the time of the Cru
sades the Saracens used solar heat in dis
tlling some of their precious liquors for
medical and cosmetic use. In these distl-
lations they made use of polished concave
steel mirrors that were made at Damascus.
Vilette an optician of Lyons, in 1862 made
a concave mirror, with focus the size of
half a gold Louis, that was so powerful
that green wood placed a yard away from
it would be instantly ignited, and copper
coin would be drilled through in less than
half a minute.
This does not exactly justify the title
but it serves to show what has been done,
and how the heat of the sun has been util-
lied.
AS for actually cooking by the suns rays
The first successful attempt was doubtless
made by the Baron of Tchirnhausen in 1851
Water placed in an earthen pot was
brought almost instantly to boil by a de-
vice he had constructed by means of mir
rors. The baron cooked eggs in this way
Sir John Herschel and Button made some
progress in experiments of this kind and
Mouchot following in their footsteps has
obtained most satisfactory results.
1t was necessary to counteract and over
come the chemical action of certain rays of
the sun before any great advance could be
made, and when this was done by the an
alyseS which were possible when the spec-
| trum was discovered, the SUMS rays were
at once put to practical use. 1t was at once
applied to the drying of fruits and yegeta-
| bles, and this can be done by the interposi-
| ton of a red or yellow glass. This serves
to prevent fermentation and the fruit dries
retaining all the sugar and valuable prop
critics, which would otherwise be lost.
Mouchot made excellent soup by cooking
with the sun. He took glass cylinder the
glass about the thickness of an ordinary
window pane, in which he set a COPPER or
wrought-iron cylinder, with the rim resting
| on the glass, and with a glass cover over it
Ih1s solar pot gave very good results On
setting 1t IN the focus of a silver-pIated re-
| fector, it boiled 0.66 gallons of water in an
hour and half.
He made in this solar pot, with a kilo-
| gram of beef and a selection of vegetables.
| a splendid soup after four hours insulation
| although the sun was at times obscured bv
| clouds ~
His next attempt was baking bread and
! by putting wrought-iron cover under the
| glass, he made an oven in which he baked
| a loaf of bread Weighing something more
| than pound in less than three hours and
| 1t was as good as any from a bakers oven
meat in the open air; by placing at a focus
! spit with a piece OF meat, it was well
cooked in three hours To avoid the fisa-
greeable taste given by the chemical rays.
he set a yellow glass before the meat.
By leading pipe from this lar TO another
containing vegetables, he soon caused the
| water to boil, and in a very short time the
vegetables were cooked. With a larger re-
tanned. Five liters of water were brought
| to boil in thirty-five minutes, and this in
| the winter time. "
This improved solar cooking stove which
| Mouchot devised is a spherical mirror
| working on a joint, SO as to be made to
| face the sun and turn the rays ON the not
which hangs from an arm and is so or
| ranged that 1t can be readily brought into
the focus OF the mirror The pot Of black
ened metal is set on glass jar, the edge
| resting on the glass covered with a eIaSs
top The reflector is of polished tin or Sill
| ver-p1ated ~
1 Now, all this described has been yerv
/ practical In its way. 1t is certainly a good
beginning. 1t should be possible for some
ingenious inventor to improve on this and
1 devise some means of utilizing some of the
vast amount of heat from the sun which
now goes to waste.