Mabch 5, 1909] ' 



SCIENCE 



391 



and of his ability to condense. But some 

 might prefer the relegation of the prolix 

 chapters which precede, to a separate volume, 

 giving opportunity for more adequate treat- 

 ment of subjects which appear to be slighted 

 over much. 



Chapter V. has 130 pages devoted to Mining 

 Gold and Silver Ores and Gravels. This is 

 well put together and presents a very fair out- 

 line of methods of mining, being very largely 

 a series of quotations from leading authori- 

 ties, although in some parts the author ex- 

 hibits his own qualifications by presenting 

 well-digested material in his own words. 



In chapter VI. a similar arrangement of 

 authoritative quotations, edited and connected 

 by appropriate remarks, makes a generalized 

 review of about 80 pages. 



Nearly 100 pages (as chapter VII.) are 

 given to statistics of production, compiled by 

 geographic areas, as usual. This work has 

 been well performed. Six appendices follow 

 in the form of tables, recapitulating in detail 

 the statistical matter previously given, under 

 practically equivalent headings. These crowd 

 a vast amount of particular information into 

 little more than 60 pages, but they are by no 

 means as complete as they might have been 

 made by seeking the aid of many local co- 

 laborers. As a convenient hand-book for 

 ready reference by busy practitioners, the 

 statistics and much of the technical matter 

 quoted may be in useful form, and probably 

 the whole will fill a want among the un- 

 tutored who require pre-digested nutriment. 

 The abundant references, though lacking the 

 personal factor which would ordinarily attest 

 their authority, add greatly to the value of 

 the work. 



The compiler has rendered good service 

 faithfully and conscientiously, according to a 

 plan apparently dictated by others. Perhaps 

 it is premature to express any opinion upon 

 certain features which might be otherwise 

 rated if one really knew the purpose of the 

 Carnegie Institution in having prepared the 

 series of texts of which ostensibly this is the 

 forerunner. Tor instance, under the head of 

 Extraction of Values, no mention is made of 



the fiux smelting of gold and silver ores, con- 

 centrated in lead and copper menstrua. Al- 

 though it is probable that this has been re- 

 served for future volumes of the series, where 

 the discussion may be more appropriate, there 

 appears throughout the present volume a 

 tendency to minimize the importance of the 

 fact that the actual weight of silver annually 

 extracted from placers and dry ores amounts 

 to nearly four and one haK times the weight 

 of gold obtained from the same source. This 

 is not an economic argument, to be sure, in 

 favor of more generous treatment of the minor 

 metal in a work purporting to deal with both. 

 But the facts are that the weight of all silver 

 extracted amounts to about fourteen times 

 the weight of the gold, and that much more 

 than three fourths of the total silver product 

 (equal in value to one third of the gold prod- 

 uct) is won by metallurgic processes designed 

 primarily for the recovery of the silver. 

 Moreover, the metallurgy of the baser ores, 

 per se, is in many respects so distinctive that 

 the collection of gold and silver therein is to 

 be regarded properly as a separate industry. 

 That is to say, the presence of the precious 

 metals in ores limits and defines processes of 

 treatment in such a- manner as to make the 

 grosser metals the real by-prodticts. 



Therefore, it would seem logical and profit- 

 able to discuss some methods to which little 

 or no reference has been made in Dr. Crane's 

 work. 



Keeping always in mind the introductory 

 words of this review, if it be fair to judge by 

 them alone, the author appears to have com- 

 passed very well the task set by the Carnegie 

 Institution. Probably no one else was better 

 placed to perform this identical service by the 

 means employed in executing it. One might 

 prefer a different mode of treatment and the 

 enlistment of others in the collaboration of 

 data not readily accessible in print. But 

 criticisms of this kind must not be permitted 

 to obscure the patent fact that the writer ap- 

 pears to the very best advantage in those 

 parts in which his subjects have given him 

 more free scope for the exercise of his own 

 abilities, and where dictates of modesty and 



