618 Reviews — Dr. Barstoto on Sulphurets. 



The opening chapter or chapters of the Arctic Instructions and 

 Manual may therefore be summed up as a code of excellent rules for 

 the guidance of the scientific observers of the Alert and Discovery. 

 They would certainly be most useful to those who, while fully con- 

 versant with one particular branch of science, may not have pre- 

 viously had the desire or opportunity of paying more than a passing 

 attention to other branches. They would bring definitely before 

 such an observer what to look for, and what to do when he had 

 found the object of his search. 



As such they are useful and interesting to others besides the able 

 observers of the Arctic Expedition. C. C. K. 



III. — Sulphurets : what they are, how concentrated, how 

 assayed, and how worked. By W. Barstow, M.D. (San 

 Francisco, A. Eoman & Co. ; London, Triibner & Co.) 



THIS little book is chiefly intended for the Californian miner, and 

 its object is to present to the reader, in a simple and concise 

 form, the nature and treatment of the Sulphides of the metals, so 

 as to save him, to some extent, the trouble of wading through a 

 series of expensive works in which the subject-matter is more fully 

 treated. The metallic sulphides, or sulphurets, are an important 

 group of mineral compounds; those which occur most abundantly 

 in nature are the sulphides of antimony, mercury, silver, zinc, lead, 

 copper, and iron. Those of the latter are of most frequent occur- 

 rence, and are the source of some of the gold. Most gold-bearing 

 rocks are coloured by the oxyd of iron, and that oxyd is often 

 plainly derived from decomposed pyrites, which is found very 

 generally associated with gold, although not chemically combined 

 with it. However, gold is often found in rock which not only 

 contains no pyrites, but is also perfectly free from discolouration. 



The characters of the chief sulphides are very briefly described, 

 too brief indeed to give their distinguishing characters. The second 

 part gives a very concise account of assaying the sulphides, and 

 also gold and silver, by the dry and wet methods. The third part 

 describes the various processes and machines for separating the 

 richer portions of the pulverised ore and other matters not desirable 

 to work, and termed concentration ; and the fourth part contains the 

 different methods for the reduction of the sulphides, by which the 

 metals they contain are extracted. The last part is devoted to a 

 brief account of the different ores when assayed by means of the 

 blowpipe, and their reactions with the various reagents to which 

 they are submitted. It seems to have been the author's wish to 

 make this an introductory guide to the more extensive and elaborate 

 works on the same subject. J. M. 



