REVIEWS 549 



regarded as the doyen of scientific metallurgy in this country. It would have 

 been a distinct loss to the industry if Professor Gowland had allowed the oppor- 

 tunity to be lost of putting the results of his life-long studies on record. 



The book gives an authoritative statement of modern practice in the extraction 

 of metals from their ores, and a discussion of the principles and conditions on 

 which the success of the processes depends, with other information necessary 

 for completeness. It is concise, mainly owing to the discrimination used in 

 omitting details which are not essential, but partly from the clear and simple 

 language chosen. The chapters dealing with gold, silver, copper, and lead form 

 the greater part of the book, and in these everything of importance has been 

 dealt with. It must have cost the author something of a struggle to omit all 

 reference to obsolete processes and matters of historical interest, considering 

 his services to archaeology, but his rule in this respect has evidently been rigid. 

 The other common metals— zinc, tin, nickel, aluminium, mercury, and the rest — 

 are treated in a more summary fashion, and the account affords little more than 

 an adequate framework for the acquisition of more detailed knowledge of these 

 subjects. 



If any part of the book were selected for special praise, it would be the 

 section on copper, on which Professor Gowland can speak with almost unique 

 authority, but the general accuracy of statement is well maintained throughout. 

 Nothing has been observed which can fairly be called a mistake, the few remarks 

 to which exception can be taken referring to matters in a state of the most 

 rapid progress, in which nothing but a weekly bulletin could be strictly up-to-date. 

 Professor Gowland apparently does not take seriously the development of the 

 counter-current decantation method in the cyanide treatment of gold and silver 

 slimed ore, a method which' has progressed of late, owing to the litigation in 

 connection with slime filtration. Then on p. 217 the statement is made that 

 " at Cripple Creek practice is divided between rolls and ball mills." This requires 

 qualification. Again, on the same page, " with dry crushed ores percolation is 

 easy" is a statement needing a little expansion. 



The book may be confidently recommended to all students of metallurgy, and 



nowadays every man engaged in practical metallurgical work is of necessity a 



student. 



T. K. Rose. 



Minerals and the Microscope. By H. G. Smith, A.R.C.S., B.Sc, F.G.S. [Pp. 

 xi + 116.] (London : Thomas Murby & Co., 1914. Price y. 6d. net.) 



It is a pleasure to record the advent of this most useful little volume. All 

 teachers and students of the subject, which finds an extensive application not 

 only in mineralogy and geology, but also in metallurgy and mining, will feel 

 grateful to the author for filling so successfully what has hitherto been a most 

 unfortunate gap in mineralogical literature. Teaching experience in this subject 

 has consistently proved that while a course of lectures can do much to smooth the 

 way for the beginner and inspire him to overcome his early difficulties, yet so new 

 to most students are the principles involved, and the manifold facts to be corre- 

 lated, that it becomes necessary to turn to a reliable book for amplification and 

 guidance. A number of large treatises of vast erudition and undoubted accuracy 

 have been published in recent years, but in the hands of the inexperienced student 

 they are apt to confuse and discourage rather than to help. For the first time a 

 small, clearly written book is available, planned out by an authoritative and 

 experienced teacher to meet the needs of those commencing a difficult study. 



