Public ledger. [volume] (Memphis, Tenn.) 1865-1893, 1868-10-21
Capt. Ericsson's last Remarkable Invention
Tho Solar Engine.

The following, from the Scientific
american, is more detailed account Of
Capt. Ericsson's new discovery, to which
allusion has been made in the papers.
It is a translation of part of the COM
munication in which he originally an
nounced the startling idea of solar
engine. he said: gg afr..
have, of late years, spent much time
and considerable means on experiments
to ascertain if the radiating heat of the
sun can be concentrated in such man
ner as to render it available for the pro-
duction of motive power. !. z
Sir John Herschel's and Mr.. Poullets
experiments relating to the radiating
heat of the sun, although interesting, are
not satisfactory, as they only deal with
low temperatures, showing how much ice
NAV be melted, or what elevation OF
temperature of water under the boiling
point may be effected in a given time on
given surface. The purpose of my in
vestigations and experiments, on the
other hand, has been to ascertain what
amount of heat can be developed at the
high temperature obtained by concen-
trating the solar rays, viz: bringing their
power to bear on a reduced surface, and
to devise the most efficient means for
effecting such concentration OF the rs-
dating heat
Apart from these preparatory expert
ments, / have also, at the commence
ment of the present year, constructed
three different motors, which 1 term
Solar Engines. One of these is actuated
by steam formed by the concentration OF
the heat of the solar rays, while the
other two are actuated by the expansive
force of atmospheric air heated directly
by concentrated radiant heat Time
will not permit, nor is it my purpose on
| the present occasion to present de-
scription of these solar engines, or the
means adopted for concentrating the
radiant heat in order to obtain the neces-
sary high temperature. | will, therefore,
limit nv essay to the consideration of
the essential part of the subject, viz: the
motive force itself With regard to this,
/ have briefly to state that my expert
ments show that at the high tempera-
ture requisite steam engines and
caloric engines, the heating power
of the sun on a surface ten feet
square will, although in itself too feeble,
evaporste on an average, foul. hundred
and eighty nine cubic inches OF water In
the hour, by means of my mechanical
contrivance for effecting the necessary
| concentration. The importance OF this
result cannot be over estimated when we
reflect that such an amount OF evapora-
ton demonstrates the presence OF sui
ficent heat to develop force capable OF
lifting 5000 pounds one foot high in
minute, thus exceeding one horse pewer.
As an incontrovertible evidence of the
capability of the sun to develop great
amount Of heat at high temperature, this
result is probably of greater importance
than any other physical truth practically
established.
The mean distance from the center Of
the sun to the earth being 2l444 times
greater than the radius of the former, it
will be found by soaring this sum, that
one superficial foot # the SUM- sur face
must heat As, ,984 times more heat than
the earth receives. We are therefore en-
sbled. on the strength Of the practical
result now positively established, TO infer
that an area Of ten feet square on the
suns surface develops heat enough 70
actuate a steam engine-not = theoret-
ical one with its small consumption,
but, a real steam engine OF 45,4s4
horse power, demanding a consump
ton Of more than 10000 pounds OF
coal every hopr. But this estimate,
based on The evaporation effected b the
concentrated radisnt heat, is far below
the actual development Of heat BY the
suu. Fully one-half Of the heat con-
veyed By the solar rays is lost during
their passage through the strosphere