The Analysis of Silicate and Carbonate Rocks: A Revision of Bulletin 305

U.S. Government Printing Office, 1910 - 239 Seiten

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Seite 17 - PP 28. The superior analyses of igneous rocks from Roth's tabellen, 1869 to 1884, arranged according to the quantitative system of classification, by HS Washington.
Seite 120 - If present with them, however, it will be separated with the strontium by ether-alcohol or amyl alcohol, and these two must then be treated by the ammoniumchromate method, given below, in order to arrive at the strontium. The barium is best estimated in a separate portion. (See "Barium,
Seite 172 - Hence, to avoid waste of time in very fine grinding, the form of crucible with cap originally advocated by Smith is very much to be preferred, since it permits, when set at an angle through an opening in the side of a fire-clay cylinder...
Seite 46 - When reckoned in per cent, the error would be such a small fraction of 1 per cent as not to be worthy of attention. The specific gravity was determined by dividing the average of the two dry weights by the difference between the dry weight and the weight of the cube suspended in water.
Seite 198 - ... absence of iron. Should there be fear of a trace of silica being present, it can be removed by a drop of hydrofluoric and sulphuric acids before weighing the barium sulphate.6 b.
Seite 30 - Fig. 1 represents a form of platinum-tipped crucible tongs devised by Dr. AA Blair many years ago. With them a crucible can be securely grasped and brought into any desired position while still hot. To the contents, if in fusion over the blast flame, can be imparted the rotatory motion so often desirable. Above all, the cover need not be in the slightest degree displaced, as when using the common form of platinum-tipped tongs.
Seite 129 - Dunnington6 has pointed out the necessity for the presence of at least 5 per cent of sulphuric acid in solutions which are to be thus tested for titanium, in order, as he concluded, to prevent partial reversion to metatitanic acid, which does not give a color with hydrogen peroxide. P.
Seite 17 - ... incomprehensible variations in the composition of some rock species or types, as shown in earlier analyses, and in not a few cases it appeared that the failure to report the presence of one or more elements had obscured relations and differences which more thorough examination showed to exist (see p.
Seite 132 - A second and a third portion of the standard can be run in and diluted and the mean of several determinations struck, when a simple calculation gives the percentage of TiO2 in the rock, the amounts in the two solutions being directly as their volumes, provided acid and interfering substances are present in each in like amounts.
Seite 79 - ... shown in fig. 17, the absorption tube, A (fig. 18), is interposed between the sulphuric-acid bulbs and the apparatus, and while a slow current of air continues to pass the gradual heating and subsequent fusion of the flux is brought about by the blast-fed sliding ring burner, R'" (figs. 17 and 18). The sodium-tungstate joint is shielded from the flame by small pieces of asbestos board, P (fig. 18), cut out so as to fit the crucible. It is well to begin fusing at the top of the mixture in the...

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