2l6 



NA TURE 



[December 24, 190S 



processes, and they certainly will not learn other 

 chemistry. 



The author seems to be unaware of the elementary 

 principle that both sides of an equation must balance ; 

 in or.e case, for example, where there is only one 

 potassium on the left-hand side of the equation he 

 has potassium carbonate upon the other side. He 

 gets over the difficulty of lack of potassium by writ- 

 ing- potassium carbonate KCO^. We may also point 

 out that ferrous sulphate is not Fe„SO^ ; one would 

 have thought that he might have found a more recent 

 equation for the action of ferrous sulphate than that 

 of Berzelius. The chapter on laboratory tests is 

 better, but until we get to chapter v. (" The Plant for 

 Cyaniding ") the author is out of his depth. It is 

 evident, however, that he does understand the practice 

 of the cyanide process. 



It is interesting to note how, as the subject of 

 " leaching " has become better known, and the 

 methods of treatment of the ore more carefully worked 

 out, so the strength of the cyanide solution employed 

 has gradually become weaker and weaker, and the ex- 

 traction of gold, more through loss of cyanide during 

 the operation, has become less. When the author comes 

 to dealing with electrocyaniding, that is to say, the 

 recovery of gold by electrical means, we wish he had 

 asked someone else who understood the subject to write 

 this part for him. He has collected many facts 

 jumbled up in a manner which would spell absolute 

 confusion to anyone not versed with electrochemical 

 methods For example, speaking of anodes, and 

 referring to platinum, he first of all says that the 

 decomposition which takes place of the electrolyte at 

 the anode is energy e.xpended, not on work, but in 

 setting free oxygen which will probably decompose 

 the electrolyte; and then he goes on to write about 

 the amount of platinum which should be liberated in 

 an ampere-hour, but we do not profess to know what 

 he means. The extraordinary thing is that all these 

 mistakes of nomenclature and misprints occur in a 

 book which is in its fourth edition. The practical 

 part of the book with reference to leaching of the ores 

 and so on can be recommended as being useful; we 

 prefer not to say anything about the rest of it. 



(2) The second book is of an entirely different class, 

 and is written in quite a different style. Any book 

 by Prof. W. Borchers upon electric furnaces is sure to 

 attract interest. We notice, however — but it is per- 

 haps not to be wondered at — that the furnaces de- 

 signed by Prof. Borchers himself loom rather large. 

 He certainly has done much pioneering work, and 

 has had some extremely good ideas, but it is to be 

 feared that others gained by his suggestions more 

 than he himself. 



The book commences with an introduction in which 

 the conversion of electrical energy into heat is dis- 

 cussed. Each chapter of the book deals with a 

 different class of furnace, and in every case the sub- 

 ject is treated in a more or less historical manner. 

 Chapter ii. is devoted to direct-resistance heating, and 

 deals in the first place with the production of 

 aluminium, and we notice on p. 23, in reference to 

 the Heroult furnace, a mistake in which the word 

 NO. 2043, VOL. 79] 



" anode " twice occurs instead of " cathode." The 

 chapter also has an account of the various induction 

 furnaces, the description of which is all too short ; this 

 is such an important branch of electrometallurgy that 

 it would have been well worth while to have given 

 a much fuller and more descriptive account of it. 



Chapter iii. deals with indirect resistance furnaces, 

 in which the substance to be heated is in contact with 

 another material, which is electrically heated ; this 

 may be a core running through the furnace, which, 

 by means of its resistance, becomes highly heated. 

 The substance which it is required to heat or reduce 

 is placed round about it, and thus receives the heat 

 from the core. Mention is also made of the kryptol 

 furnace. Direct arc heating is the subject of the next 

 chapter, and here the author deals with carbide fur- 

 naces, and refers to the acetylene arc furnace of 

 Berthelot. The phosphorus arc furnace of Readman 

 and Parker is also described. Indirect arc heating is 

 the subject of the next chapter, such, for example, as 

 is employed in zinc furnaces for the distillation of the 

 metal. 



The last two chapters are devoted respectively to 

 the arrangement of furnaces for different modes of 

 heating, and to the construction of electric furnaces in 

 general. A short appendix by the translator is 

 devoted to some recent developments in electric steel 

 furnaces. 



The book is decidedly useful, is very well illus- 

 trated, and carefully translated, but at times the 

 description is scrappy, and we are rather afraid the 

 reader who knows nothing about furnaces will hardly 

 get sufficient information to be of service. 



(3) The third book deals with hydro-electric practice, 

 and is an extremely valuable contribution to the sub- 

 ject. The author has written it for two classes of 

 readers. The first part is intended for those who have 

 no engineering training or experience — that is to say, 

 for the layman who may desire to know something 

 about water-power schemes, and to whom it is neces- 

 sary to have some idea as to whether it would be 

 advisable to risk anything in the undertaking or not. 

 The second part, entitled " Designing and Equipping 

 the Plant," is written for the student, and the aim 

 of the author has been to make the treatment of this 

 part of the subject complete in all its phases, with the 

 exception that he presupposes a knowledge of the 

 principles of surveying and of the rudiments of hydrau- 

 lics, hydrostatics, and dynamics. Occasionally in the 

 first portion of the book, in order to make himself 

 perfectly clear, the author gives definitions which are 

 rather unnecessarily elementary ; for example, is it 

 necessary to say that all the water consumed by 

 vegetation and vapourised is evaporation, and the 

 portion which runs into the stream is the run-off? 



The enormous amount of trouble which Mr. von 

 Schon has taken in the compilation of his facts can be 

 seen from the table of rivers, drainage areas, and low 

 monthly flow, which extends from p. 10 to p. 26, and, 

 of course, there are many other tables and diagrams 

 interspersed throughout the volume. 



Chapter ii. is entitled " Power Opportunity," mean- 

 ing to say the possibilities of obtaining water front 



