This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1905 Excerpt: ...of the containing vessel after sintering together (fig. 11). Surmising that we had accidentally hit upon the approximate melting temperature, a fresh charge of like material was prepared and the same experiment carefully repeated, except that the temperature was carried up to 12o60 and maintained there for 3o minutes. ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1905 Excerpt: ...of the containing vessel after sintering together (fig. 11). Surmising that we had accidentally hit upon the approximate melting temperature, a fresh charge of like material was prepared and the same experiment carefully repeated, except that the temperature was carried up to 12o60 and maintained there for 3o minutes. Instead of showing the melting to be complete, the slides (Plate XXI) looked precisely like the first, save that the lanes of glass were somewhat wider and the crystal fragments relatively smaller than before. Further trials under precisely the same conditions, with the temperature increased to 12250 (Plate XXII) and 125o0 (Plate XXIII), respectively, for like periods of time, showed only more advanced stages in the same process. In the latter case the remaining crystal fragments were relatively very small compared with the separating lanes of glass, but the orientation of the tiny particles still remained perfectly undisturbed. The evidence contained in this series of slides shows plainly that we have here an unfamiliar condition--a case of a crystalline compound persisting for a long time above its melting temperature for a given pressure. Albite or orthoclase glass sinters tightly at 8oo0. At the temperature where melting began, therefore (below 12oo0), the charge consisted of crystal fragments of microscopic size embedded in a large vitreous mass of the same composition and known temperature. These fragments melted so slowly over the 5o0 included between the first slide and the last, with the rate of heating slow (1 in 2 minutes) and the upper temperature continued for 3o minutes, as to leave considerable portions unmelted at the close. Furthermore, the extreme viscosity, of which further evidence will be given directly, and the absence of...
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