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NA TURE 



\7uly%, 1875 



student he has retained the old chemical formulas. 

 Surely it would have been better to swim with the times 

 and adopt the new atomic weights, taking care to abolish 

 all doubtful tests, and adding the latest and most accurate 

 methods of analysis. Many of the latest and most delicate 

 methods of mineral analysis are entirely omitted, such as 

 Bunsen's methods for the detection of arsenic, antimony, 

 selenium, molybdanum, uranium, &c. The work in 

 question is divided into two distinct parts ; the first con- 

 taining descriptions of the different apparatus and re- 

 agents used, and a " Systematic Course of Blowpipe 

 Analysis ; " the second, styled " Determinative Minera- 

 logy," makes use of the knowledge acquired in the first 

 part to determine the mineral species under examination. 

 The " Systematic Course of Blowpipe Analysis " is adapted 

 from the later editions of Plattner's work on Blowpipe 

 Analysis, edited by his successor. Prof Richter ; the 

 " Determinative Mineralogy " is a translation of Von 

 Kobell's " Tafeln zur Bestimmung der Mineralien," tenth 

 edition. Generally speaking, students do not take kindly 

 to " Tables," but Prof. Brush has made them more in- 

 viting by arranging the minerals having the same base 

 into groups, and studying them in order. This is an 

 excellent arrangement, and the distinguished author 

 deserves the gratitude of students for thus lightening their 

 labours. Too many mineralogical works of the present 

 day exhibit a harum-scarum kind of classification, which 

 simply bewilders the inquiring student and leaves him 

 in greater confusion than before. The first part of the 

 work opens with descriptions of various kinds of blow- 

 pipes, and the manner of using them, also the fuel 

 used to obtain the requisite flame. Here, under the 

 headings " Reducing " and " Oxidising " flames, are de- 

 scribed very clearly the characters of the two flames, 

 with very good engravings showing the zones. The 

 methods for preparing the various reagents required are 

 trivial and should ^have been omitted ; for instance, we 

 are told to prepare pure carbonate of soda by taking 

 " four, or five ounces of commercial bicarbonate of soda 

 free from mechanical i7Hptirities," &c. We should be 

 glad to know where Prof Brush obtains his commer- 

 cial bicarbonate of soda so free from impurity, as the 

 manufacturer deserves encouragement. Chapter II. com- 

 mences the " Systematic Course of Quahtative Blow- 

 pipe Analysis," describing the reactions of the elements 

 and their combinations in the " closed tube and open 

 tube," and on " Charcoal as a support." Under the 

 latter heading a very neat and novel method is given for 

 overcoming the great difficulty experienced sometimes in 

 keeping the assay in its place on the charcoal. Let those 

 who wish to work in comfort for the future buy the book, 

 and find the method therein. 



Further on, the colours imparted to a flame by different 

 metallic salts are described, but all of them, with the excep- 

 tion of copper, sodium, potassium, lithium, and calcium, 

 might have been left out with perfect justice, for no one could 

 decide what metal was present from a simple examination 

 of the coloured flame as described ; that could only be 

 done by means of the spectroscope. Then follow " The 

 uses of Fluxes and Roasting," and " Fusion with Borax," 

 which are simply adaptations from Plattner, and the 

 tables given in this division are literal translations from 

 the same author, which may also be said of the division 



" Fusion with Salt of Phosphorus." It is only fair to say 

 that in the preface to his book Prof Brush states : " The 

 main authorities used in the original preparation and 

 later revision of the chapters on blowpipe analysis 

 were the works of Berzelius and Plattner. The third 

 and fourth editions of Plattner, the latter edited by Prof. 

 Richter, have been chiefly consulted." The whole work 

 seems to confine itself almost entirely to blowpipe analysis 

 by the dry method, ignoring very frequently much easier 

 and quicker methods of detection by the wet method of 

 analysis. A few instances may be given, viz., copper 

 when associated with nickel, cobalt, iron, and arsenic by 

 the dry method, proceed as follows : — " Separate most of 

 the cobalt and iron by treating with borax on charcoal, 

 the remaining metallic globule is fused with pure lead, 

 and then boric acid is added ; this last dissolves the lead 

 and the rest of the cobalt and iron, while most of the 

 arsenic is volatilised. The cupriferous nickel globule 

 which still may contain a little arsenic is treated with 

 salt of phosphorus in the oxidising flame ; the bead ob- 

 tained will be dark green while hot, and clear green when 

 cold. This last green is caused by a mixture of the 

 yellow of oxide of nickel and the blue of oxide of copper.'' 

 What a complicated and tedious process ! Now let- us 

 consider the wet method well known to chemists, but not 

 mentioned amongst the " characteristic reactions " in the 

 first part of this book. Dissolve the mineral in nitric 

 acid or nitro-hydrochloric acid, get rid of the excess of 

 nitric acid, precipitate the copper by means of sul- 

 phuretted hydrogen, dissolve this, precipitate in nitric 

 acid, and add excess of ammonia, when the liquid at once 

 acquires the splendid well-known blue colour. The arsenic 

 will be present as arseniate of ammonia, and will not inter- 

 fere with the reaction. Even more easily can traces of 

 copper be detected by Bunsen's neat method, as follows : — 

 Fuse the assay on a charcoal^ match with carbonate of 

 sodium ^in the reducing flame, treat the fused mass with 

 distilled water in a porcelain basin, gather together (by 

 means of a small magnet) the metallic particles of cobalt, 

 nickel, and iron, and remove them ; dissolve the remaining 

 metallic copper in nitric acid ; take up a drop of this solu- 

 tion by means of a glass rod and place it upon a strip of 

 white filter-paper, add a drop of ammonia to the moistened 

 paper, and observe the decided blue colour where the drop 

 of solution was placed. Thus, by the time the student had 

 blundered through the dry method of discovering copper, 

 a skilful chemist would almost have determined the 

 percentage of copper present in the assay by some 

 volumetric process. Singularly enough, the above method 

 is mentioned several times incidentally in the second part, 

 entitled *' Determinative Mineralogy." Under the heading 

 " Iron," no mention is made of the well-known reaction 

 between ferric salts and ferrocyanide of potassium, but 

 doubtful borax bead reactions are very prominent. The 

 characteristic precipitate obtained by mixing soluble lead 

 salts with bichromate of potassium is omitted also. 

 Chapter IV. opens with "Determinative Mineralogy." 

 These tables are the best part of the book. The student 

 must be very dull indeed who fails to determine a mineral 

 by the use of them. The method of studying the different 

 minerals is excellent, as the , specimen under examination 

 is soon brought into a group ; and by ,'glancing at the 

 characteristics of each mineral in that group, and com- 



