Evening star. [volume] (Washington, D.C.) 1854-1972, 1884-10-25
The Sums Heat and Power.


In Il recent number of Nature the distin-
gushed engineer Capt. John Ericsson sets forth
some Investigations which he made during the
summer soltice of this year upon the tempera-
ture Of the suns surface. These Investigations
form part Of memorable series of studies in
solar physics. one practical result OF which has
been the construction of working appliance
for the actuatiOn OF machinery by the use of
heat derived from collected solar rays. 1t is
certainly noteworthy to find the renowned en-
gineer who, more than two score years ago revo-
lutlonized naval warfare by the Princeton, tn e
first war steamer ever built with her motive
power protected. and again, twenty years later.
dictated reconstruction to the worlds navies by
the Monitor, the famous victor of Hampton
Roads, and who after another interval of twenty
years produced the DESTROYER, which ia designed
to ruin great foreign irOncads that may attack
our harbOrs, now, in his Octogenarian days. pur-
suing recondite philosophical studies, whose
fruits will inure to the peaceful occupations of
manufactures and commerce.
The power developed by Capt. Ericsson's sun
motor Indicated that the temperature of the
suns surface is very great. But the cylindrical
heater OF the motor, constructed solely for the
purpose OF generating steam or expanding air.
Is Tor various reasons not well adapted as it's
constructor has said, for an exact determine
ton Of the amount of surface exposed to the &C
ton of the reflected solar rays. Accordingly, for
this latter purpose, he constructed a solar pyro-
meter. which has been erected in this city during
the present year. 1t is an instrument of large
dimensions, a pOlygOnal reflector. composed of
series OF inclined mirrors. and provided with
central heater Of cOnical form, acted upon by
the reflected radiation in such a manner that
each point of its surface receives an equal
amount OF radiant heat in a given time.
The central doctrine which Capt. Ericsson
frs established by demonstration and then as
sumed as the basis Of the Investigations Just
ln6 n1i 10 ft,ofs fhA
by solar radiation is as the density of the rays"
without attempting to reproduce the mathe-
NAUTICAL processes resorted to, or to describe in
detail the apparatus Of observation, it is enough
to say that Capt. Ericsson reaches conclusions
remarkably close to those of Sir Isaac Newton.
and totally different from those Of POuillet.
Vcaire Sainte-Clairi Deville, and others, who
have assigned comparatively low temperature
to the suns surface. Newton. in estimating the
temperature to which the comet of 1880 was
subjected when nearest the sun, based his cal
culatiOns on the result OF his practical obserya-
lions that 1.-The maximum temperature pro-
duced by solar radiation was One-third of that
OF boiling water; and he found accordingly, that
the comet was exposed to temperature of
$3.50. O0Oo, an intensity exactly 2OOO times
greater than that of red-hOt iron, at tempera-
ture of S40o." Capt Ericsson adds this dednc-
ton in the article referred to:
The distance OF the comet from the solar surface
being equal TO one-third Of the SUMS radius 1t will
be seen that, In accordance with the Newtonian
doctrine, the temperature to which 1t was sub
1ected indicated solar intensity OF 2,9s6. 1000 F.
The results Of the experimental Investigations
carried out by Capt. Ericsson correspond re-
marhably to those just recorded. They are thus
briefly stated:
The diffusion of the solar rays acting on the
twentyinch heater being in the ratio of to 10 241
the temperature OF the solar surface cannot be less
than $3.50 50 multiplied by 1924 equal to 727o
f. This underrated computation must be accepted
unless 1t can be shown that the temperature pro-
duced by radiant heat Is not inversely as the dYu-
sion OF the rays.
The high temperature here assigned to the
SUMS surface of course greatly contrasts with
the estimates of those French investigators who
do not consider that it reaches $1,000 cent?
grade.
AS TO the sun motor. apart from general ap-
plicability to certain classes OF work, it must
apparently be specially useful in all regions like
those. for example, OF the southwestern terri
tories, that are almost always under the direct
rays Of the sun in the daytime.