from The Manufacturer and Builder,August 1870 issue.
MR. A. Mouchot, a professor in Tours, France, has recently published a pamphlet, in which he communicates his experience about the technical application of solar heat. The article bears the title, “The Heat of the Sun and its Industrial Uses.” In it the French savant has laid down in a clear and sound manner, as the result of observations extending over nine years, what, in 1868, the Swedish engineer, Ericsson, well known for his invention of the caloric machine, had announced to the world, to wit, that it is actually pos- sible to concentrate the solar heat in such a manner as to heat our technical steam and pneumatic apparatus. To us, the consequences which must be the result of an extensive application of the projected machines are of great interest. On this point, the author expresses himself in the following manner: “If Egypt, in spite of her efforts, finds it so difficult to elevate herself from her ruins, this decline is less to be ascribed to the exhaustion of her old physical resources—which, in the powerful sun and the fertile inundations of the Nile, have always remained hers—than it is to the lack of an inexpensive fuel. People have to use dry camel-dung, and at a price of coal of fifty or a hundred francs per ton, laborers can not be readily substituted by machinery. In that country, machines driven by solar heat may be effective, because it lies under a sky on which ‘the sun rises in an eruption, and sets in a sea of flames;’ where, for months, no cloud darkens the lord of heaven ‘—the old guardian-god of the Nile land. And the same holds good for the tropics, under which the heat is great and fuel rare, and where the labor of man and beast is very inconsiderable.” “And the time will arrive,” says the author of the above- named pamphlet, “when the industry of Europe will cease to find those natural resources, so necessary for it. Petroleum-springs and coal-mines are not inexhaustible; but are rapidly diminishing in many places. Will man, then, return to the power of water and wind? or will he emigrate where the most powerful. source of heat sends its rays to all? History will show what will come. Countries which have maintained large nations always needed rest the same as the fields.” No doubt the future will show in what direction “sun-machines” will be practically available. Any one who considers the facts will have to agree that tropical countries offer some hope of success for them; in which case, with the realization of an ancient idea, (Hero of Alexandria having already described a pump driven by the heat of the sun,) great changes would have to take place in many respects. Meantime, let us await results patiently.