556 



NA TURE 



[April i i, 1S95 



one to which the mineral more especially owes its com- 

 mercial importance. While slate is sandwiched in 

 between the gems, under the heading "Silica and 

 Silicates," clay is relegated to " Aluminium." 



In a general treatise upon mineral deposits, exception 

 may fairly be taken to the absence of any mention of 

 coal ; the author excuses himself on the ground that fuel 

 forms a special subject too vast to be included within the 

 compass of his book. The overwhelming importance of 

 coal seems, on the other hand, an additional reason for 

 finding it a place in a work which is practically an 

 encyclopasdia of applied geology ; besides, if fuel is to be 

 omitted, why are natural gas and petroleum inserted .' 



In a gigantic work of this description, it is impossible 

 for an author to avoid some errors. Five mistakes in 

 spelling Welsh words in the first three lines of p. Ixxviii. 

 will not be looked upon as a heinous crime by the 

 average Englishman, who himself feels that he is skating 

 upon thin ice when he is dealing with the orthography 

 of names of places in the Principality ; however, these 

 are not the only cases of misprints which might be 

 noticed. 



The geo;jraphical tables, occupying forty-five pages, 

 form a useful feature in the book ; an alphabetical list is 

 given of the principal minerals worked in each country, 

 together with references to the pages where they are 

 described. These tables and the index of localities take 

 the place of a general index, which is not supplied. 

 Small maps inserted in the text are of much assistance 

 in enabling the reader to follow the author's descriptions ; 

 the total number of woodcuts, 390, may seem large, but, 

 scattered as they are through more than 1800 pages, 

 they are not as numerous as one would like. Great 

 pains have been taken with the bibliography, and Prof, 

 de Launay's lists will often bring into notice original 

 papers which would otherwise have passed unnoticed. 



Though too expensive for the pockets of ordmary 

 students, the book will find a place in the libraries of all 

 mining schools and geological and engineering societies, 

 and it is sure to be frequently consulted with profit by 

 geologists and mining engineers. 



Moreau's work has a totally different object to that of 

 de Launay ; the latter is a record of observc^l facts, 

 whilst the former, dealing solely with metallic ores, is 

 mainly devoted to general principles. After describing 

 briefly the classifications of ore deposits proposed 

 by von Groddeck, de Lapparent, Phillips, Whitney 

 and Raymond, the author suggests one of his own, 

 viz. : — 



(A) Stratified deposits. 



(B) Eruptive deposits. 



(C) Deposits m pre-existing cavities. 



(D) Substitution deposits. 



Mineral veins are classed under the head (C), and 

 apparently Moreau does not admit that they may some- 

 times be substitution deposits. 



Two ch ipters are devoted to disquisitions upon the 

 origin of mmeral ve ns, an I are based upon the works of 

 Uaubrde, Lyell, Elle de lieaumont, De la Uechc, 

 Hcnwoid, Moissenet, Ccikie, and others; Vogt's recent 

 researches and theories remain unnoticed. 

 N 1. 132S. VOL. 5 I 1 



Chapter v., which treats of the chemical and physical 

 characteristics of ores, and the earthy minerals which 

 accompany them, should have been omitted ; and the 

 same remark applies to the chapters upon qualitative 

 testing, quantitative assaying, dressing and smelting. 

 These subjects cannot be taught in a few pages, and are 

 better studied in the ordinary text-books. 



Chapter vi., largely borrowed from von Groddeck, 

 Phillips, Kuchs and de Launay, contains descriptions of 

 well-known characteristic ore deposits. The important 

 iron ores of the Secondary rocks are dismissed in a very 

 cavalier fashion, for, strange to say, no mention is made 

 of the great iron-field of the Department of Meurthe and 

 Moselle, Lorraine and Luxemburg. 



The most valuable part of the book for mining men will 

 be found in two of the concluding chapters, which deal 

 with the study of ore depo>its from a purely commercial 

 point of view. They are full of useful hints and warnings, 

 not only to the engineer who is examining mining pro- 

 perties offered for sale, but also to the capitalist who 

 is meditating their purchase. M. Moreau is evidently im- 

 bued with many of the ideas which were running through 

 the brain of Mr. J. H. Collins when he delivered his 

 recent presidential address to the Institute of Mining and 

 Metallurgy. The more deeply counsel of this kind is 

 taken 10 heart, the better will it be for investors in mining 

 enterprises. 



A few errors in the names of well-known geologists 

 are inexcusable. It is strange that any one should write 

 " Sir RichurJ Lyell '' ; " Sir Logan Foster, Whitney," is 

 evidently meant for "Sir William Logan, Foster and 

 Whitney " ; even Elie de Beaumont's name is not always 

 spelled correctly. " Gossan " is a Cornish and not a 

 Welsh term, as supposed by the author. 



OUR BOOK SHELF. 



Elementary Text-book of Afetallurgy. By A. Humboldt 

 Sexton, F.I. C, &c. (London: Griffin and Co., 1895.) 



This book is intended, for those who are commencing 

 the study <if metallurgy, as a kind of preparalory course 

 to that of Prof. Koberis-Austen. as given in his '■ Intro- 

 duction to the Study of Metallurgy," which the student 

 is advised to read after digesting the contents of Prof. 

 Sexton's manual. The work is got up in good stjie by 

 tlie publishers, and printed in a clear and distinct manner. 

 Willi the general arrangement there is very little to 

 complain of ; but the same by no means can be said of 

 the subject-matter, which contains many errors, and the 

 definitions are often expressed in such crude language 

 •hat a student might be easily misled in taking his first 

 lessons in metallurgy from its pa>;es. 1 he following 

 examples may be cited :— P. 3: M.ilk-abiliiy. This Is 

 the property of being expanded into sheets. Duciility: 

 Tills IS the property of being drawn into wire. A small 

 quantity of antimony in lead is said to make it quite 

 brittle. P. 4 : Lead may be drawn into wiie if means 

 betaken to prevent the metal being subjeil to stress. 

 P. S ; With reg.ird to tensile testing, the author says 

 that elongation takes place mostly near the point of 

 fracture. P. 46 : There are but two neutral substances 

 in general use, ginphile and chrome iron ore. P. 89 : 

 Fluor spar is said to be used 10 increase the qu.antily of 

 slag. On pp. 92 and 121 : C below 5 is lerined wroutjht 

 iron, and steel when C is between 5 and 15 ; while on 



