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Quantitative Classification 
of Igneous Rocks 
Based on Chemical and Mineral Characters 
With an beeen esd Review of the Devel- 
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aw his Nineteenth Century 
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: age the basis on which a ‘proper classification 
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magmatic and rock names; and the last part of the book is 
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Petrologists in fac last few nia for a ne kgf fame 
System into which could be fitted the recent large additions 
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286 pp., 8v0, cloth, net, $1. 75; cloth, $1.91 
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Lectures on the Calculus of 
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By OSKAR BOLZA, Ph.D. 
Of the Department of Mathematics in the 
Bai iversity of Chicago 
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156 
