Boys' Second Book of Inventions

by Ray Stannard Baker

CHAPTER V
HARNESSING THE SUN
The Solar Motor

It seems daring and wonderful enough, the idea of setting the sun itself to the heavy work of men, producing the power which will help to turn the wheels of this age of machinery.

At Los Angeles, Cal., I went out to see the sun at work pumping water. The solar motor, as it is called, was set up at one end of a great enclosure where ostriches are raised. I don't know which interested me more at first, the sight of these tall birds striding with dignity about their roomy pens or sitting on their big yellow eggs—just as we imagine them wild in the desert—or the huge, strange creation of man by which the sun is made to toil. I do not believe I could have guessed the purpose of this unique invention if I had not known what to expect. I might have hazarded the opinion that it was some new and monstrous searchlight: beyond that I think my imagination would have failed me. It resembled a huge inverted lamp-shade, or possibly a tremendous iron-ribbed colander, bottomless, set on its edge and supported by a steel framework. Near by there was a little wooden building which served as a shop or engine-house. A trough full of running water led away on one side, and from within came the steady chug-chug, chug-chug of machinery, apparently a pump. So this was the sun-subduer! A little closer inspection, with an audience of ostriches, very sober, looking over the fence behind me and wondering, I suppose, if I had a cracker in my pocket, I made out some other very interesting particulars in regard to this strange invention. The colander-like device was in reality, I discovered, made up of hundreds and hundreds (nearly 1,800 in all) of small mirrors, the reflecting side turned inward, set in rows on the strong steel framework which composed the body of the great colander. By looking up through the hole in the bottom of the colander I was astonished by the sight of an object of such brightness that it dazzled my eyes. It looked, indeed, like a miniature sun, or at least like a huge arc light or a white-hot column of metal. And, indeed, it was white hot, glowing, burning hot—a slim cylinder of copper set in the exact centre of the colander. At the top there was a jet of white steam like a plume, for this was the boiler of this extraordinary engine.

Side View of the Solar Motor.

"It is all very simple when you come to see it," the manager was saying to me. "Every boy has tried the experiment of flashing the sunshine into his chum's window with a mirror. Well, we simply utilise that principle. By means of these hundreds of mirrors we reflect the light and heat of the sun on a single point at the centre of what you have described as a colander. Here we have the cylinder of steel containing the water which we wish heated for steam. This cylinder is thirteen and one-half feet long and will hold one hundred gallons of water. If you could see it cold, instead of glowing with heat, you would find it jet black, for we cover it with a peculiar heat-absorbing substance made partly of lampblack, for if we left it shiny it would re-reflect some of the heat which comes from the mirrors. The cold water runs in at one end through this flexible metallic hose, and the steam goes out at the other through a similar hose to the engine in the house."

Though this colander, or "reflector," as it is called, is thirty-three and one-half feet in diameter at the outer edge and weighs over four tons, it is yet balanced perfectly on its tall standards. It is, indeed, mounted very much like a telescope, in meridian, and a common little clock in the engine-room operates it so that it always faces the sun, like a sunflower, looking east in the morning and west in the evening, gathering up the burning rays of the sun and throwing them upon the boiler at the centre. In the engine-house I found a pump at work, chug-chugging like any pump run by steam-power, and the water raised by sun-power flowing merrily away. The manager told me that he could easily get ten horse-power; that, if the sun was shining brightly, he could heat cold water in an hour to produce 150 pounds of steam.