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. 1904 Excerpt: ...the same in the hornblende analysis as in the rock analysis. These ratios are as follows: Oxides in hornblende andpulaskoxe of Square Butte. The titanic acid in the hornblende was calculated from the rock analysis and can not, therefore, be taken into account. The amount of magnesia in the rock is so small that the ...
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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. 1904 Excerpt: ...the same in the hornblende analysis as in the rock analysis. These ratios are as follows: Oxides in hornblende andpulaskoxe of Square Butte. The titanic acid in the hornblende was calculated from the rock analysis and can not, therefore, be taken into account. The amount of magnesia in the rock is so small that the ordinary variations of analytical work might render this ratio not very exact. The ferrous irons and the limes show close agreement, based on larger quantities, but if they are correct the ferric irons can not be. Taking everything into account, it seems probable that in either the rock or the hornblende the amount of ferrous to ferric iron has not been very correctly determined, and that the error is in the rock determination, which should be about 0.86. Classification in prevailing systems.--This rock has been called a sodalite-syenite, and Bosenbusch, mindful of the rather small amount of feldspathoids present, has placed it under the alkaline syenites rather than in the nephelite-syenite family proper. Under this system of classification, especially if the variable nephelite and sodalite is considered, the rock forms a connecting link between the two families. Classification in the new system.--In the new system of classification the position of the rock is seen in the next table, in which its norm is calculated from the chemical analysis. It is of interest to note that this gives 70.56 percent of alkalic feldspar, while Lindgren's calculation gives 66 per cent, the difference arising in the 3 per cent of analcite in his calculation. The 23 per cent of hornblende of the mode is replaced by anorthite, olivine, and iron ores in the norm, making all told 18.11 per cent, the difference being due to the fact that no femic alkalic constituents appe...
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