Reviews. 



SUMMARIES OF THE LITERATURE OF ECONOMIC GEOLOGY. 



I. 

 Edwin C. Eckel. 



With the present issue the title of this section has been changed to con- 

 form to an enlargement in its scope. A brief outline of the plan which the 

 writer purposes to follow may be of service to readers. 



Papers and books relating to the economic geology of the United States 

 will be summarized, so far as possible. Discussions of economic developments 

 in foreign countries will be excluded, unless containing matter of general 

 interest. Publications devoted largely or entirely to the technology of any 

 mineral industry will not be summarized ; but as such technologic papers 

 appear to be of increasing interest to workers in economic geology, they will 

 be listed by title, with occasionally a brief note to indicate their scope. 

 Reports or papers containing statistical or compiled data only will be neither 

 summarized nor listed. 



The expansion of the scope of this series of summaries will necessitate 

 the exclusion from it of many papers which would have been noticed under 

 the old arrangement. The writer has planned, therefore, to continue the old 

 series in Municipal Engifieerittg, under the title "Recent Publications on 

 Structural Materials." 



Adams, G. T. " Principles Controlling the Geologic Deposition of the 

 Hydrocarbons." Trans. Am. Inst. Mitt. Eng., Vol. XXXII ; advance 

 separate, 7 pp. 



The author notes the present unsatisfactory condition of the literature on the 

 hydrocarbons, in so far as their geologic interlation and the principles governing the 

 origin of their economically valuable deposits are concerned ; and applies to these 

 problems certain principles allied to those stated by Van Hise for ore deposits. The 

 principal difference, in this regard, between hydrocarbons and ores is that the latter 

 are carried in solution, while the former are largely associated with the transporting 

 water merely in a condition of mechanical mixture. The author then discusses the 

 effect of the inferior specific gravity of the hydrocarbons, as compared with water; 

 the different effects which will be produced, according as the hydrocarbon is merely 

 miscible with, or soluble in, the transporting water; and the possibility that 

 separations of the hydrocarbons, equivalent to those accomplished by fractional dis- 

 tillation, may be effected by differences in degrees of solubility, or in the character of 

 the rock traversed. 



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