June 21, 1894] 



NATURE 



171 



ed to great developments of practice, which it would be 

 A-ell to consider when the time com;s for revising the 

 votk. If, however, the book be considered as a whole, 

 Mr. Louis has undoabtedly offered the best account of 

 ;old milling that has yet appeared. 



In concluding this review of both books, it may be well 

 to remind the reader that, of all the phases of metallurgic 

 art, that which leads to the consideration of gold is the 

 most interesting. It is certain that modern chemistry 

 had its dawn in the study of the properties of gold, while 

 from the fourth to the fifteenth century chemists thought 

 of little else than transmuting base metals into precious 

 onts. The protest of the metallurgist against such 

 wasted labour was, however, felt as early as the middle of 

 'he sixteenth century, and a book, " Rechter Gebrauch 

 J'.'Mchemei," was published (1531), which by its title 

 showed that the " right use of alchemy " was to bring 

 chemical knowledge to bear upon industry. Hence it is 

 that the modern metallurgist makes strenuous efforts not 

 to transmute base metals into gold, but to extraci it eco- 

 nomically from a mass of material of which fifteen million 

 parts may only contain one part of gold. It would be 

 Miost mteresting to know at what cost this is done, but 

 ipon this point Mr. Rose is unable to give us very 

 definite information, though it is evident he considers 

 that the ounce of fine gold which sells for about /4, 

 should be produced for about £1, if it is to yield a profit 

 to the miner and metallurgist. 



Both books under review have each their special 

 value. Mr. Rose has adopted a broad treatment of a 

 very interesting subject, while Mr. Louis has shown 

 how important a single branch of the metallurgy of gold 

 can be. 



OUR. BOOK SHELF. 



Geology. By Charles Bird, B A., F.G.S. Pp. viii., 

 430. (London: Longmans, Green, and Co., 1894,.) 



Like the previous volumes in the series of Advanced 

 Science Manuals published by Messrs. Longmans, this 

 satisfies the reciuirements of the advanced stage of the 

 [-)epartmcnt of Science and Art. A sub-title informs us 

 that the book is "a manual for students in advanced 

 classes and for general readers.' But while we believe 

 ihe work to be well suited for use among students 

 learning geology on South Kensington lines, we should 

 be sorry to recommend it to the general reader, that is 

 to say, to the person who reads-geology for the pleasure 

 It affords, and not with the idea of eventually exercising 

 the acquired knowledge in an examination room. The 

 author has collected together an abundance of facts, but 

 the student who has to digest them all deserves our 

 sympathy. There are, however, several good points 

 about the book. One of these is the chapter on the 

 industrial uses of rocks, in which numerous buildings, 

 monuments, and other structures in London and else- 

 where are noted as examples of various kinds of build- 

 ing materials. References to the practical application 

 of geology to water supply, agriculture, and mining are 

 also frequently made, and will doubtless endear the book 

 to the man who measures the value of a science by its 

 direct use in commercial life. 



Mr. Bird has taken advantage of the splendid 

 collection of photographs of geological forma- 

 tions published by Messrs. Wilson, of .Aberdeen. 

 The illustrations obtained from this source are 

 among the best In the book, and many of them have 



NO. 1286, VOL. 50] 



not previously appeared in any work on geology or 

 physiography. Another excellent feature in the pictorial 

 part of the book is that a number of the figures of 

 fossils, rocks, and minerals are from photographs of 

 objects in the Jermyn Street Museum. The illustrations 

 of some of the minerals are, however, not very in- 

 structive. The only use of a figure is to assist the 

 student to distinguish the characteristics described In 

 the text. It is doubtful, however, whether the figures of 

 hornblende, heavy spar, tiuor spar, iron pyrites, galena, 

 and sulphur, given on pp. 24-30, are any help to identifi- 

 cation, though one or two of them may serve to illustrate 

 crystalline habit. 



Scarcely any attention is paid to the microscopical 

 examination of rocks, and we have vainly consulted 

 the Index for references to the use of the seismo- 

 graph, earth-tremors, the permanence of ocean basins, 

 secular movements of the sea, and several other subjects 

 of recent work. Even if these matters are not specially 

 mentioned in the syllabus which the book has been 

 designed to meet, they might have been Included with 

 advantage. W'e note that Eozoon is still referred to as 

 •' the most ancient fossil known," though Its mineral 

 formation has been clearly made out. But taken 

 altogether the book is trustworthy, and the student who 

 assimilates its contents need not fear to present 

 himself for the examination In .Advanced Geology held 

 by the Department of Science and Art. 



The Ne'v Technical Educator. \'o\. III. (London, 

 Paris, and Melbourne : Cassell and Company, 1894.) 



The previous volumes of this series have been duly noticed 

 in these columns, where it was pointed out that they very 

 adequately fulfilled a useful purpose. The present volume 

 Is up to the level of its predecessors, treating as it does of 

 every-day general engineering and other matters in their 

 broadest sense. The information given is certainly of very 

 recent date, and this is as It should be, from every point 

 of view. There are, however, a few statements made that 

 are not quite accurate ; for Instance, on p. 102 we are 

 told that among other things wrought Iron Is supplied 

 commercially In the form of rails. What railways now-a- 

 days use iron rails? They are things of the past, steel 

 having years ago taken their place. Further on we read 

 that steel plates may now be obtained up to 70 square 

 feet in area. Surely double this area would be nearer the 

 mark ? On page 105 we are told that fullering a rivetted 

 joint means to caulk it with a narrow edge tool (as at C, 

 Fig. 3). This Is certainly not the case ; to fuller a joint 

 means to " set up '' the plate edge with a tool at least the 

 thickness of the plate, whereas the method shown in the 

 figure is generally known as "narrow edge caulking." 

 Further on it Is stated that looseness at the rivets Is 

 sometimes guarded against by caulking the rivet-heads. 

 This is all very well, but loose rivets should be cut out 

 and replaced by sound ones. 



Under the heading of " various types of steam 

 boilers" we find much useful information, the locomotive 

 type being represented by the standard boiler used on 

 the Lancashire and Yorkshire Railway ; it is, however, 

 stated that in some cases the water spaces are carried 

 down and across the bottom, thus constituting an ash- 

 pan and called a wet bottom. This no doubt is true of 

 a few boilers built at Crewe, but In the majority of cases 

 the wet bottom Is unknown to modern railway practice. 

 In this chapter George Stephenson is said to have intro- 

 duced the blast pipe in locomotives. Surely this inven- 

 tion is due to Richard Trevithick .' 



The marine type of boiler is represented by one made 

 by the Central Marine Engine Company, West Hartle- 

 pool ; it is of the single-ended type, and fitted with Fox's 

 corrugated flues. Of water tube boilers there are two 

 standard examples, viz. the Babcock and Wilcox for 

 stationary engines, and the Thorneycroft for marine and 



