June io 1909] 



NA TURE 



423 



" Carnage and Freight Charges. It is not too 

 iiuich to sav that the whole success of the exploitation 

 of new paper-making fibre hangs entirely upon this 

 item, the majority of many fibres which have been 

 brought to the notice of the trade being suitable, but 

 impracticable solely on account of these and similar 

 tommercial considerations." 



For looseness of technical exposition note the 

 following (p. 150) : — 



" The main difificultv experienced is the liability of 

 paper to stretch when damped, and various methods 

 nre devised to obviate this, either by employing paper 

 which stretches verv little when damp, or by making 

 the paper partially waterproof before use." 



We also observe such expressions as " the value of 

 a vegetable plant for paper making " (p. 23), which is 

 repeated on p. 26 in the following : — " The percentage 

 of cellulose in the vegetable plants, employed more or 

 less in the manufacture of paper." On p. 25 we also 

 note, " The alternative treatment with bromine and 

 ammonia," whereas what is intended is the alternate 

 treatment. 



More serious are the author's frequent errors in 

 statement of matters of fact; thus hydration is con- 

 fused with hydrolysis (p. 27) — " Cellulose is only 

 oxidised by acid and alkali if treated under severe 

 ■conditions"; again, "Cellulose benzoate is obtained 

 .\ hen alkali cellulose is heated with benzoyl chloride 

 and excess of caustic soda " (p. 31). The description 

 of " artificial silk " is generally inaccurate, with an 

 unfortunate misprint of " five " for " fine." 



It must not be thought that we are hypercritical in 

 citing these examples, and it is only fair to students and 

 the reading public thus to direct attention to defects 

 which are general. It is pleasant, on the other hand, 

 to commend the author for his extremely interesting, 

 original observations, sucli as the investigation of the 

 process of beating (pp. 179-85), and also his chapter 

 on the dyeing and colouring of paper pulp. In con- 

 clusion, such a work can be commended to a certain 

 class of readers, notably those representing the 

 stationers or consumers, and also those who require 

 general information without regard to close accuracy. 

 There is certainly room for a work of this character, 

 and with a rigorous revision the volume might be 

 made a useful addition to the literature of paper 

 making. 



HINTS FOR MINERAL COLLECTORS. 



Mineralien-Sammliingen. Ein Hand- titid Hilfsbuch 

 ji'ir Anlage iind Instandhaltun g mineralogischer 

 Samrnhmgen. By Dr. Wolfgang Brendler. I. Teil. 

 Pp. viii + 220. (Leipzig: Wilhelm Engelmann, 

 iqoS.) Price 7 marks. 



MOST of us have in our youth been impelled to 

 form a collection of objects, such as stamps or 

 butterflies, which come within the purview of every- 

 day life, but few have essayed minerals, partly be- 

 c.uise, except to those actually dwelling in a mining 

 district, crystallised minerals in the natural state are 

 almost unknown, and partly because it is on first 

 NO. 2067, VOL. 80] 



acquaintance perplexing to understand how minerals 

 may be determined. A brief experience soon shows 

 that colour, the most obvious physical character, is 

 no trustworthy guide. It is, indeed, impossible, with- 

 out some knowledge of the physical and chemical 

 characters of minerals, even to arrange a collection, 

 much less derive any pleasure or satisfaction from 

 it Dr. Brendler has endeavoured to smooth the path 

 of the collector by providing in this slender volume 

 all the information necessary for the determination 

 of the ordinary characters of minerals. If we judged 

 by the slight interest taken in this country in min- 

 eralogical science, we should have anticipated that the 

 demand for such a book would have been too small 

 to justify its publication, but it appears from Dr. 

 Brendler's preface that in Germany a more encour- 

 aging state of things prevails. 



Rather more than two-thirds of the volume is 

 occupied with the morphology of crystals and the dif- 

 ferent types of crystalline symmetry. The usual 

 treatment of the subject is followed, and little com- 

 ment is called for. As is customary in most German 

 text-books, prominence is, unfortunately, given to 

 Naumann's symbolical method of denoting the forms, 

 although Miller's simple notation is also mentioned. 

 We notice that it is styled the " Grassmann-Miller " 

 notation, a conjunction which might suggest that 

 Miller introduced some modification or adaptation of 

 a method originated by Grassmann. It is true that 

 the latter made use of the same notation in a pub- 

 r.cation issued in 1829; nevertheless, it was solely 

 due to the revelation of the simplicity of this notation 

 produced by the publication in 1863 of Miller's masterly 

 tract that it came into universal use among active 

 workers in crystallography, and it is probable that 

 Miller arrived at the notation quite independently. 

 Dr. Brendler is, perhaps, unaware that Whewell de- 

 scribed the same notation in a paper read before the 

 Royal Society on November 25, 1824 (Phil. Trans., 

 1825, p. 90). We have dwelt upon the point at 

 some length because this is, we believe, the first 

 time that Miller's claims have been apparently dis- 

 paraged. 



Son-.e thirty pages are devoted to a brief discussion 

 of the ordinary physical characters — cleavage, hard- 

 ness, specific gravity, pleochroism, double refraction, 

 and so on— and a few pages deal with the usual blow- 

 pipe reactions. 



The concluding chapter, entitled " Die Mineralien- 

 sammlung," forms the most original, and, indeed, the 

 most interesting, part of the volume. Here the author 

 gives many invaluable hints, which are familiar to 

 curators and are perhaps trifling in themselves, but 

 for want of which considerable difficulties may arise 

 as a collection grows. He describes a convenient 

 type of case for housing and exhibiting the specimens, 

 shows how the damage that might arise from the 

 effects of light, damp, or dirt can be obviated or 

 minimised, and suggests suitable mounts for the 

 specimens exhibited in the tops of the cases and suit- 

 able travs for those placed in the drawers underneath. 

 His advice that all specimens be numbered chrono- 



