The sun. [volume] (New York [N.Y.]) 1833-1916, 1876-09-17
A REM1RkABLE IyYEyrrox

Archinedcs set fire to Roman ralevs q, 3D., -.
OF Syracuse. His experiment, once conadered
mythical, was repeated by Button. who n,
means OF a burning glass, made Of numerou,
small mirrors, klndlod wood at a consIder,,i,
distance, melted tin, silver, and various uino-
ais, and brought iron to a rod heat. snbse
quenty French physicisf, Pouillet. succeeded
in measuring the caorinc intensity Of the SUM
radiation, while an Itall n savant. Mconl scer
tanned and classified the transmisslve quali,io,
OF conductors, and { different reflective DOW.
ers OF polished metallic surfaces. Sufficient
data, apparently had been accumulated for the
next step, which his now been taken, anc
which contcmplites tho mechanical application
of the solar heat.
The inventor Of the solar steam engine, which O.
Is now In actual operation at Tours Il French
man named Nouchot formerly professor OF
mathematics, hut for many yeirs employed b7
the late Emperor In his private laboratory at
Meudon. Before attempting to apply the solar
ray to the genera ion OF steam, he undertook to
demonstrate by simple aud inexpensive con-
trivince It's availability as n culinary irent lII
FIRST achievement In this direction was portal
ble soup pot. This was cylindrical coppe;
vase placed in glass bowl. tho whole being
shut in by a glass cover and tho suns heat
was concentrated on the app ratus by means
OF a silver plated cylindrical ren ,ctor. In this
way an excellent SOUP OF beef and vegetables
was prepared In less ;hsn four hours. The
utensii. moreover, W - transformed into an oven
by substituting disc OF beaten iron for the cop
per vase under the glass covorcle. Here bread
WIS baked within three hours which proved to
be Ia all respects equal To ordinary bakers
loaf, being thoroughly leavened, and having
nrm, brown crust Since the roasting Of meat
does not require the s,me quantity OF heat rs
was performed In the open air under the SOLE
influence OF the solar reflector, before which
was hung a spit garnished with piece OF beef
II was found necessary to avoid TIE use Of hut
ter. which tho chemical solar rays would have
converted into butyric acid. giving the meat
disagreeable smell and favor. Even this onjec'
ton, however, could be eliminated bv Inter
posing a sheet Of yellow or red glass. Finally
with trivial notifications, the apparatus was
adapted to distiation, alcohol being evolved
from wine after a lapso Of forty minutes.
Subsequently, VI. Mouchot sought to devise
process Of obtaining dynamic effects with tho
solar heat, and his first successful experimental
that end was made about ten years ago. wnet
he completed for the Emperor Napoleon small
steam engine, whose motive power was eener
ated by the new agent. II Il, however. the
more elaborate and effective machine which hs
has been enabled 10 construct at Tours by sub
sdy from tho Coun ;ll-General of the depart
ment. to which We would direct attention.
The most striking feature Of the apparatus Is
a large truncated cone, "A sort OF gigantic lamp
shade with the concayity turned upward. Tbs
material ia copper, lined on the inside with
thin sheet Of solid silver. On the smaller base
Of this truncated cone rests copper cylinder
having a vertical axis Of the same height and
blackened on its outer surface. Tho drum,
4. 81, D. al
Is closed at the top By a hemsphetical cap, aud
is developed by glass case Identical with ITSELF
In form. The whole constitutes a novel speclei
Of generator designed to raise water TO the boil
ing point and beyond, by the sole action OF the
SUMS rays cunccntratei on the cylinder from
the polished inner surface OF the conical re-
Hector. BY means OF feeding pipe and pump
the copper boiler Il filed with water up to At out
two-thlrds OF It's height, while a glass tuoe and
manometer communicating with tho interior.
indicate the water level and the pressure OF tho
steam. The boiler IL, OF course. furnished with
a safety valve, which discharges the vapor when
ever the pressure exceeds given number OF It
mospheres. The generator, in short, may bs
supplemented with all the customary accesso'
fies, and, therefore, offers the requisite
curlty.
The prin cipal com ponent OF the machine, the
metallic mirror, Is eight feet in diameter a; the
larger base, about forty inches at the sm,llcr
and thirty-two inches high. The interior walls
are Of polished silver because this metal il
recognized as the best reflector Of the heat rays,
but coating Of britannia plate would answer
very WELL The face OF the conical mirror Is in
clined TO its vertical axis at an angle OF forty
five degrees, because with this inclination the
incident RAYS parallel to that axis ars reelected
perpcudlculary to IL, and give a focus OF max.
imum inteuaitv. The huilar IA NJ amman ha-
cause among common metals this is the best
heat conductor, and II is blackened on the OUT
side because black surface has the property 81
absorbing all tho caloriac rays. Again, It ID
sheathed with case Of glass. becau.e tais sub
stance Is most easily trayersed by the beams OF
solar heat, whose emergence, moreover. Il har
the property Of resisting after they have been
transformed into obscure rays on the exterior
OF the boiler These applications Of physical
laws are OF course familiar, having been re-
sorted to I'm practice long before they were
capable u scientific explanation.
The boiler proper in the solar machine Of
Tours Is composed Of two concentrlc barrel4
both Of "copper" the larger. which alone Is visible
having tn same height the ref ctor aud the
smaller, inner drum about one-third l,ss. The
water IS lodged between these two envelopes
thus constituting an annular cylinder rathei
more than an Inch thick, while through the In
terror barrel, which remains empty, pass the
feeding tube and the steau-cuuducting Pipe
Between the glass case and the boiler there iss
constant interval Of two inches filled b.
sheath OF verY hot air. We need not point out
that toe reflector, 10y reason Of the diurnal and
annual revolutions Of the earth. does not occunl
the samo position toward tho sun nj every hom
OF the day or at every season Of the year. 40
cordingly Mouchot's generator is not stationary
but so cOntrved as to turn through an angle OF
Is degrees per hour about an axis parallel VITA
that OF the earth-in other words, To follow tho
apparent diurnal movement Of the sun, md
moreover e. lean gradu Ny toward that axis In
conformity with what Is called the solar decliu,
alton with TINS arrangement the beat utilized
Is ~ all times nearly uniform.
The results attained toy this generator were
accounted highly satisfactory. altuough II Ia
probable they VIII be speedily surpassed with
a perfected aupAl Aus. linus twenty ltres Of
water introduced into the hulpT at eight O'Clock
Va the morning required but torty minutes ia
produce steam having pressure Of two atmos.
pheres, ana the yapor afterwhrd eXpt nded riu-
Idly To a Pressure OF i've itmu sphere . the limit
liked by tire boilers thickness. which was lest
Ia ~ the tenth Of an inch. Toward noon ul me
same day the steam rose from the tempe tTc
Of 10Y Centigrade t. 1859, or a uressurc OF i've
atmo-phere-, iu less than "a Qulitcr Of an hOur
Finally, about one O'Clock M the afternoon, the