Evening star. [volume] (Washington, D.C.) 1854-1972, 1908-04-05
HARVESTING THE SUN

beyond experimental value. In the begin
ming of the twentieth century. however, was
the first practical employment of a solar en-
CINE. This set up at the ostrich farm,
Pasadena, California, for the purpose OF pump
ing water, and it has continued for some years
in successful operation. Here again IS the
truncated conical mirror, which Is thlrty-three
feet SIX inches in diameter at the top and
fifteen feet at the bottom. The rays of the
sun are thus received on seventeen hundred
and lightweight facets, whence they are
focused on the boiler.
The mass of glass and iron composing the
mirror is moved by suitably arranged clock
work, SO that it is automatically held with its
axis directed toward the sun. The boiler is
carried on the same frame, moving, OF course.
as the mirror moves. 1t has length OF
thirteen feet six inches, and contains about
ten cubic feet of water, with eight cubic feet
of steam space. From the boiler, steam IS
conducted to a compound engine operating
centrifugal pump. To set the machine IN
operation it is turned by hand until its axis
points at the suns disk; then the clockwork
is set going. 1t is stopped by merely turning
the mirror away from the sun. The whole
apparatus is so nicely balanced with its weight
on roller bearings that hand pressure OF only
a few pounds IS necessary to SHIFT ITS posi-
ton The engine develops fifteen horsepower,
with a pumping capacity of fourteen hundred
gallons minute.
Thinks He Has Found 1t
THE great difficulty with engines OF this
character is that the cost of construction is
almost prohibitive, while the mirror surfaces
are i'll calculated to withstand the ravages of
the elements. For these reasons the solar
motor in its present form cannot be widely
employed. Now, however, a Pennsylvania
engineer announces that he has perfected an
apparatus altogether unlike the foregoing,
whereby solar heat is cheaply converted into
mechanical energy His method is so simple
that it promises success.
The inventor has constructed as his working
model a large hotbed sixty feet in length by
eighteen in width. 1t is made by letting a
wooden box into the ground, and covering
this with double top of dollhouse glass, hav-
ing one inch OF air space between the roofs.
The hotbed is filled with iron pipes painted
black These form the generating plant In
our climate, the pipes are filled with ether; but
in the tropics water serves the purpose. The
ether in the pipes is converted into vapor,
passes through the engine, enters a condenser,
and then returns to the hotbed. Thus the
circuit is a closed one. The whole effect is
secured without any use of fuel; the accumu-
lated heat of the sun is sufficient to vaporZe
the ether
The inventor declares that with this appa-
ratus he gets temperature of from three
hundred and fifty to five hundred degrees. In
the tropics this would mount easily to thou
sand.
Plants are to be established in the tropics
where the fierce heat combined with low
humidity offers the best advantages. There
is almost no limit to the power that might
thus be drawn from the sun. Changed to
portable form, in liquid air or storage bat
teries, the genie of that greatest lamp, the sun,
would be ours to command.