5U 



NA TURE 



[October 4, 1894 



did ia the cass of Rankiae's engineering treatises, the 

 p355ibility of the work becoming rapidly obsolete. 



The subjec: has been divided into the following 

 chapters : i'' Occurrence or manner in which the useful 

 minerals are found in the earth's crust ; (2) prospecting 

 or search for minerals ; (3) boring; (4) excavation; 5) 

 supporting excavations ; (6) exploitation or working 

 away of minerals; (7) haulage or transport along roads ; 

 (S) winding or hoisting in shafts; (9) drainage; (10) 

 ventilation ; (11) lighting ; (12) descent and ascent ; (13) 

 dressing; (14' principles of employment; (15) legisla- 

 tion; (16) condition of workmen; and (17) accidents. 

 The mining of coil is not dealt with ; a special treatise 

 hiving been published, as a companion volume, by Mr. 

 H.W. Hughes. 



In the first chapter, the time-honoured definition of 

 mineral veins as the contents of fissures is wisely 

 expanded by the author. Veins, he states, are tabular 

 mineral deposits formed since the enclosing rocks, and 

 either occupying cavities formed originally by fissures, 

 or consisting of rock altered in the vicinity of fissures. 

 There can be no doubt that many so-called fissure-veins 

 are really substitutional deposits, and the necessity for 

 some change in the definition is apparent. The author 

 enters a timely protest against the use of the word 

 "gangue"for the veinstone, lode-stuff, or matrix. Mis- 

 translated from the German Gang (vein) into French, 

 and thence into English, it has lost its original meaning, 

 and should be consigned to oblivion. 



The fascinating but perplexing subject of the formation 

 of mineral veins is clearly and concisely dealt with. 

 Sandberger's lateral secretion theory, assuming that the 

 minerals were leached out of the adjacent rocks and 

 re-deposited in the vein cavity, is regarded by the author 

 as not entirely proven. This view, it is interesting to 

 note, is shared by Posepny, who in a paper read, last 

 year, at the Chicago Congress, published since the 

 appearance of Dr. Le Neve Foster's treatise, expresses 

 the opinion that Sandberger's theory suffers from several 

 fundamental defects, and by being accepted as a simple 

 and welcome explanation of the genesis of ore-deposits, 

 has hindered the progress of knowledge. 



In studying the mode of occurrence of minerals, 

 abstract definitions are not sufficient. The student must 

 see how they can be applied in practice. The author, 

 therefore, gives a carefully chosen series of examples of 

 the modes of occurrence of the more important minerals 

 arranged in alphabetical order. The thoroughness with 

 which he deals with this section is evident from the fact 

 that lie gives accounts of the occurrence of carbonic acid, 

 of petroleum, and of ice. Liquefied carbonic acid is now 

 .1 regular article of commerce in Germany, whilst the 

 American ice trade affords employment to 12,000 men, 

 looo horses, and 100 steam engines. Full descriptions 

 of the mining of ice, to which the author n-ight usefully 

 have given references, have been published in Ilelland's 

 Norwegian treatise on mining, and in a paper read in 

 1883, by Mr W. P. Blake, before the American Institute 

 of Mining Engineers. 



The eleven chapters dealing with mining proper cover 

 some 450 pages, and include descriptions and illustra- 

 tion? of all the important appliances used in mining 

 work, including the most recent inventions. Indeed, if 



NO. 1301, VOL. 50] 



fault can be found with this section, it is that the author 

 devotes too much space to inventions so recent that their 

 advantages have not been thoroughly tested. The 

 description of the Franke drill, for example, the smallest 

 and lightest boring machine in practical use, introduced 

 last year at the Mansfeld copper mines, occupies more 

 space than that of the modern stamp battery. 



The chapter on dressing, under which term the author 

 includes the processes by which the miner prepares his 

 product for sale, or by which he extracts a marketable 

 product from it, covers 100 pages, and is of special 

 mterest. Hearing in mind the needs of teachers, the 

 author supplies useful information enabling the student 

 to construct ingenious models of glass-tubing, iS:c., to 

 illustrate the principles of motion in water and in air, 

 and the construction of dressing appliances. .\ mixture 

 of like-sized grains of coal, calcspar and galen.i, 

 minerals of distinctly different colour and specific 

 gravity, is used in these experiments. 



The author's classification of the dressing processes 

 employed is quite novel. There are three main divisions, 

 according as the process is effected solely by mechanical 

 means, or is based upon the physical or chemical pro- 

 |)erties of the minerals treated. The main divisions are 

 subdivided in the following manner : — 



I. Mechanical processes. — (l) Washing in order to 

 separate clay, mud, and sand; (2) hand-picking; (31 

 breaking-up, subdivision, or shaping ; (4) agglomeration 

 or consolidation ; (5) screening or sifting — that is. 

 classification according to si/e. 



II. Processes depending upon physical properties. — 

 (l) Motion in water ; (2) motion in air ; (3) desiccation ; 

 (4) liquefaction and distillation ; (5) magnetic attrac- 

 tion ; (6) separation according to degree of friability. 



III. Processes depending upon chemical properties. — 

 (i) Solution, evaporation, and crystallisation ; (2) atmo- 

 spheric weathering ; (3) calcination ; (4) cementation or 

 precipitation by iron ; (5) amalgamation. 



This classification cannot fail to be of the utmost value 

 to the student, even if the subdivisions are not strictly 

 defined in reality. .\ carefully considered classification 

 of this char.acter converts dressing into a rational science, 

 instead of leaving it, as is the case in the existing 

 treatises on the subject, an unsystematic collection of 

 heterogeneous facts. One cannot but regret that the 

 exigencies of space have compelled the author to give 

 but meagre information regarding some of the most 

 important mechanical appliances. Dressing is, however, 

 a special subject of sullicient importance to command a 

 literature of its own, and it is to be hoped that the author 

 may some day be induced to expand his classification 

 into a complete treatise. 



The 71 1 illustrations given by the author are clear and 

 effective ; and in all important cases the scale is indi- 

 cated. The frontispiece, representing an overhand slope 

 at the 274-fathoin level at Cam Urea Mine, Cornwall, 

 from a photograph by Mr. J. C. ISurrow, is a most artistii 

 piece of work and a triumph in underground photography. 

 With his characteristic minute accuracy in detail and in 

 no.nenclature, the author has introduced the expression 

 " 274-fathoms level " in place of the usual " 274-fathoni 

 level.'' No doubt he can bring forward arguments in 

 favour of this practice, which he adopts thro-.igho'.it the 



