NATURE 



433 



THURSDAY, SEPTEMBER lo, 1903. 



RECENT MINERALOGY. 

 Mineralogy : an Introduction to the Scientific Study of 

 Minerals. By Henry A. Miers, D.Sc, M.A., P'.R.S. 

 Pp. xviii + 584; with two coloured plates and 716 

 illustrations in the text. (London : Macmillan and 

 Co., Ltd., 1902.) Price 255. net. 



THE author of this work has various qualifications 

 for the difficult task undertaken by him, a task 

 which has occupied the leisure hours of many years 

 of an otherwise busy life. For thirteen years he was 

 closely associated with the most beautiful and extensive 

 of mineral collections; during that time he became 

 tiioroughly familiar with such objects as are described 

 in his book, and attained scientific distinction by reason 

 of the thoroughness and delicacy of his varied scientific 

 researches ; further, he visited not only all the best 

 collections in the world, but also many noted mineral 

 localities, and viewed the specimens in their own 

 homes. He introduced, and for several years taught, 

 the subject of crystallography to the students of the 

 City and Guilds Technical Institute, invited thereto, 

 and encouraged therein, by that far-seeing and 

 enthusiastic chemist Prof. Henry Armstrong ; he thus 

 prepared the way for the brilliant discoveries since 

 made by his crystallographic pupil Dr. Pope, and at 

 the same time not only became familiar with the 

 difficulties met with by students, but was compelled 

 to discover the best ways of surmounting them. 

 During the last eight years he has been at O.xford as 

 occupant of the Waynflete chair of mineralogy, in 

 succession to the veteran mineralogist and crystallo- 

 grapher Prof. Maskelyne, and by his development of 

 mineralogical study in that university has more than 

 justified his appointment. 



The volume, though announced to be merely " an 

 introduction to the scientific study of minerals," im- 

 mediately impresses even a superficial observer with 

 the magnitude of the subject, for its pages are at once 

 large and numerous (584). But the reader, on open- 

 ing it, instead of being immediately repelled by the 

 obvious details and technicalities of a difficult subject, 

 is at once attracted by the artistic character of the 

 workmanship, for both paper and type are excellent, 

 and the pages are adorned with no fewer than 716 

 illustrations, most of them of a style to which we are 

 quite unaccustomed. Every artist knows the difficulty 

 of making even a fair representation of the aspect of 

 minerals, and both authors and students have thus had 

 to remain content with mere diagrammatic figures in 

 illustration of mineral "habit." In this case the 

 author has been able to make many experiments by 

 presuming on his relationship and exercising the 

 artistic patience of a sister; as a result, they have 

 evolved a series of figures most of which leave little 

 • to be desired ; these are process reproductions of shaded 

 drawings of actual, not imaginary, specimens, and, 

 through the emphasis given by the artist to the leading 

 lines of the figures, are as good substitutes, in tw:. 

 dimensions, for the actual specimens as can be wished. 

 NO. 1767, VOL. 68] 



Among the most striking are Figs. 402, flos ferri; 

 407, calcite showing conchoidal fracture and cleavage ; 

 422, diamond; 437, cryolite; 447, blende; 478, 

 corundum; 486, rutile ; 506, quartz twinned; 519, 

 chrysoberyl; 554, witherite; 587, chiastolite; 627, 

 harmotome. For the diagrammatic figures of 

 crystals, the author is indebted partly to the same 

 artist. Miss J. Miers, and partly to the assistant, Mr. 

 R. Graham, whom he has trained in crystallography 

 and perhaps represented, on p. 263, in the very act 

 of crystal measurement. Further, there are two 

 coloured plates which have been executed at the Oxford 

 University Press by the three-colour collotype method, 

 and are the outcome of much experiment; unfortu- 

 nately, the method is as yet found to be too costly for 

 general use. One of these plates represents the simple 

 biaxial figure shown by a section of an orthoclase 

 crystal when viewed in the polariscope by blue, green, 

 and red monochromatic lights respectively ; the other 

 represents the complex figure yielded by the same 

 section when viewed by white light. The actual 

 chromatic effect of the " inclined dispersion " so 

 characteristic of the mineral is thus beautifully re- 

 produced by photography instead of being diagram- 

 matically represented, as is usually the case, by a more 

 or less plausible arrangement of colours. The trouble 

 taken, and the expense incurred, to obtain this result 

 are characteristic of the book in general. 



The author himself points out that the treatise is 

 no exhaustive introduction to the study of mineralogy, 

 and that he has deliberately abstained from giving a 

 systematic account of the modes of occurrence of 

 minerals, their geological distribution, their origin, 

 their alterations, and their artificial production. 

 Indeed, the account and discussion of the essential 

 characters of only the more prominent of the minerals 

 which are so common as to be found in all museums 

 occupies a volume which, to put it mildly, is quite as 

 large as a student of average strength can conveniently 

 carry about and handle ; the other subjects are of 

 necessity left for treatment in one or more later 

 volumes. 



The present volume is divided into two nearly equal 

 parts; the first deals with the properties of minerals 

 in general (286 pages) ; the second gives a description 

 of the more important species (244 pages) ; these are 

 followed by 28 pages of tables and a most elaborate 

 and useful index (22 pages). One of the tables gives 

 in a compact form a classified arrangement of the 

 mineral species and a simple chemical formula for 

 each, thus enabling the mind to grasp more readily 

 some of the chemical relationships of the species. Of 

 the tables useful in the practical determination of 

 minerals, the most noteworthy are those giving the 

 arrangement of the species according to the increasing 

 magnitude of the mean refractive index, the bire- 

 fringence, the optic axial angle, and the specific 

 gravity respectively. 



Part i. is subdivided into four books, treating of (i) 

 crystalline properties (179 pages); (2) general proper- 

 ties (23 pages); (3) relations between the properties 

 (30 pages) ; (4) description and determination of 

 minerals (44 pages). Of the three latter and shorter 



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