Explorations and field-work of the Smithsonian Institution in .. . hour, thereby keeping the mirroraxes approximately at right angles to the rays of the sun. Each mirror focused the sun rays upon a glass focus tube, abouti^ inch in exterior diameter, comprising three concentric tubes ofPyrex glass. The inner tube, about 4 inch in diameter, contained ablack liquid, aroclor , which almost totally absorbed sun rays andcould withstand a temperature of 350° C, or 640° F. without boiling 2 SMITHSONIAN INSTITUTION or decomposition. The inner tube was hermetically sealed within theouter, preserving a
Explorations and field-work of the Smithsonian Institution in .. . hour, thereby keeping the mirroraxes approximately at right angles to the rays of the sun. Each mirror focused the sun rays upon a glass focus tube, abouti^ inch in exterior diameter, comprising three concentric tubes ofPyrex glass. The inner tube, about 4 inch in diameter, contained ablack liquid, aroclor , which almost totally absorbed sun rays andcould withstand a temperature of 350° C, or 640° F. without boiling 2 SMITHSONIAN INSTITUTION or decomposition. The inner tube was hermetically sealed within theouter, preserving a very high vacuum between them. The third tube,lying between them, was merely a further barrier to hinder the escapeof heat. All three focus tubes were connected by a pair of header tubes ofcopper to a boiler of the fire-tulie type, lying l:)ehind and above themirrors. In order to accelerate the circulation of the aroclor ab-sorbing liquid from the focus tubes to the boiler, a small motor wasused to operate a little piston pump within the liquid circuit. Steam. Fig. I.—Abbots solar cooker employed on Alount Wilson during summerexpeditions since 1920. was raised to pressures exceeding 100 lbs. per square inch, and usedto drive a small steam engine for exhibition purposes. On one occa-sion, with the cooperation of the National Broadcasting Company, ashort conversation was broadcast by solar power. Although this installation had much promise and some interestingperformance, and although as regards the collection of solar radiationand the absorption of it to produce heat, and even the preservation ofthe heat for useful purposes, the devices were economical and highlyefficient, defects in the machine as a whole became immediately appar-ent. To appreciate them, let us recall: SMITHSONIAN EXPLORATIONS, I936
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectscienti, bookyear1912
