Action of Sunlight on Glass

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Tuttle, Morehouse & Taylor, 1867 - 19 Seiten
 

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Seite 11 - ... interesting report on this subject. He wrote : " I would mention a curious fact, in which the sunbeams have, if I may say so, done something in the art of penmanship; not only on the surface, but by inscribing characters through the body of the glass; and, though the matter is based upon causes wellknown by experience, yet there has probably never before been so striking an instance of their effect known. I am in possession of a plate of glass which has been used as a windowpane for more than...
Seite 3 - Gaffield does not propound any theory to explain these changes of color, which, under our sunny skies, probably take place much more rapidly than in the different and less clear atmosphere of England. "Some writers point to the presence of oxyd of manganese in the original composition of window-glass, and some to the oxyd of iron, as a chief cause. " Some writers have peculiar theories about the different classes of the sun's rays. Some may think the change referred to, a molecular or chemical one...
Seite 19 - ... the causes and exact operations of this interesting power of the sun's rays to paint the products of art, as they do so beautifully and wonderfully the works of nature on the mountain, in the forest and field.
Seite 15 - ... neutralized, and the glass is thereby made of a light color. When the sunlight acts upon glass thus made, the nice equilibrium between the oxygen of the iron and the manganese is disturbed, and sometimes the yellow, and sometimes the pink or purple color is produced.
Seite 7 - Pelouze,§ who wrote in the Comptes rendus of 1867, said : "I do not believe that there exists in commerce a single species of glass, that does not change its shade in sunlight.
Seite 15 - ... theorize upon the results which we witness. While I may not theorize, I may help others to do so by stating the interesting part which some metallic oxides play in coloring, and the oxide of manganese in decolorizing glass. In almost all kinds of window glass and glass-ware, materials are necessarily used which are not perfectly and chemically pure. The sand, the carbonate or sulphate of soda, the lime and other constituents, one or all, contain slight impurities, and almost always oxide of iron....
Seite 7 - ... summer, from greenish or bluish white, to a yellowish white, or light yellow, a deep and deeper yellow, until it becomes a dark yellow or gold color ; and, in some Belgian sheet specimens, a gradual change, commencing in a few weeks in summer, from brownish yellow to deeper yellow, yellowish pink, pink, dark pink, purple, and deep purple.
Seite 18 - I have never yet met any one who has seen glass in original imported packages, of the purple color made by exposure to sunlight, and until I do, I shall adhere to my opinion, that all purple or rose colored glass which is seen in our city windows, was made so by said exposure.
Seite 19 - This action of sunlight must not be confounded with that called " rust," or " stain," which is occasioned in some glasses having an excess of alkali in their composition, by exposure to the atmosphere, and manifests itself in two ways ; first, by a disintegration and roughening of the surface, sometimes producing all the effects of ground glass; and secondly, by an efflorescence and apparent formation of an infinitesimal coating of oxide upon the surface, on which the play of the sun's rays produces...
Seite 2 - ... produced by reflection therefrom, has been conclusively proved by grinding off about one-sixteenth of an inch from both surfaces and the four edges of a duplicate exposed specimen, which, after repolishing, still exhibited the same yellow color. . " The glasses exposed were all what are called colorless window-glasses, although they varied in tinge and hue from the whitest French plate to the darkest green English sheet-glass. " An experiment for four months, from July to November, on really...

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