Mav 3, 1906] 



NA TURE 



" ncilhing- more or less than matter in the process of 

 bfi "i}iing." 



" Bioi,'cn may be regarded as the intermediate state 

 briwecii free electricity and condensed electricity which 

 «.• call matter— the hiatus between electricity as we 

 knew it and matter as we know it; the missing link 

 thai bears 



' The heavy and the dreary weight 

 Of all ihis unintelligible world.' " 



Wo cannot follow the author further with his new 

 ' X.ilurphilosophie," but it is interesting to point out 

 that, although he says life-activity is a phenomenon 

 of matter, he is far from being a materialist. For 

 matter, he tells us, is really mind-stuff, and " atoms 

 are nothing more than ideas." We have always 

 suspected that this would turn out to be the case. 



As an interesting book on a perennially interesting 

 theme " The Origin of Life " will probably soon pass 

 into a second edition, and we therefore note a few 

 errata. " Wiesmann " (p. 56), " Debois " (p. 175), 

 '• Luduc " (p. 208), " nucleosus " (p. 136), " mytosis " 

 (p 137), are obvious misprints. We suppose that the 

 •' chlorophyll " referred to thrice on p. 135 is a mis- 

 print for chromatin, but the author seems confused 

 in his picture of a typical cell. Mitosis is not " the 

 multiplication of the chromosome"; the centrosome 

 is not " the inner portions of the nucleus, or 

 nucleolus"; and we cannot speak of "the karyo- 

 kinesis of the centrosome." There are several such 

 errors indicative of haste, and there is a disconcert- 

 ing lack of correspondence between some of the figures 

 and the references to them in the text. 



The author is so enthusiastic over his radiobes and 

 iitli nuclei that we almost wish we could believe more 

 in the importance of either of them. The former 

 seem to us very far from possessing «- 1 of the n 

 properties of the simplest living creature we know ; 

 the latter seem to us ingenious fictions too remote 

 from everyday physiology to have even suggestive 

 value. But these are merely our opinions, and it may 

 be that Mr. Burke will, by more precise observations 

 and more restrained theorising, justify the views of 

 those who have hailed him as a pioneer and a prophet. 



J. A. T. 



PRINCIPLES AND PRACTICE OF POTTERY. 

 La Ceramique indnstrielle. Chimie-Technologie. 



By A. Granger. Pp. x + 644. (Paris: Gauthier- 



Villars, 1905.) Price 7 francs. 



THIS is an excellent example of the technological 

 handbooks which the young Frenchman and 

 German find ready to their hands when they pro- 

 ceed from school or college to take up industrial work, 

 and which, in so many businesses, the young English- 

 man just as conspicuously lacks. At the present 

 moment there is no English book on pottery manu- 

 facture, other than indifferent translations of a French 

 and a German book, to which a student of the prin- 

 ciples of pottery manufacture can turn, and these deal 

 most accurately with processes unknown or unused in 

 England. 



The volume in question is, as is perhaps inevitable, 

 NO. 1905, VOL. 74] 



stronger on the theoretical than on the practical side. 

 The first nine chapters, comprising about half the 

 book, give a clear and logical account of the physical 

 and chemical properties of the materials used in the 

 preparation of pottery paste and glazes of all de- 

 scriptions, together with laboratory methods of 

 chemical analysis and such methods as have been 

 devised for testing the degree of fineness, plasticity, 

 and tensile strength of the various natural clays and 

 clay mixtures, as well as a theoretical discussion of 

 the behaviour of complex mixtures of silicates (clays 

 and glazes) when fired at varying temperatures up to 

 their fusion point. .\11 this is put forward with that 

 clearness of expression and logical precision of 

 arrangement that seem to come so naturally to ihc 

 French teacher. 



The feeling cannot be resisted that the author, with 

 the very best intentions, has covered too much ground. 

 It wouid seem as if he had attempted to describe every 

 known process, apart from its merits or demerits, 

 with the result that the student is overwhelmed with 

 methods, and at the same ^ime left without a clue 

 as to the suitability of particular methods in special 

 circumstances. In the section on silicate analysis, for 

 example, the ordinary methods of treatment are given 

 for silicates soluble in strong acids, and the methods 

 of attack with carbonate of soda, lime, baryta, oxide 

 of lead, boracic acid, and hydrofluoric acid for the 

 insoluble silicates, yet not one of the processes is 

 described in such detail as would enable the student 

 to conduct an analysis, and the refinements and correc- 

 tions introduced into the ordinary methods of silicate 

 analysis by Hillebrand, without which it is impossible 

 to guarantee one's results, are never mentioned. In 

 the same way, in the sections dealing with the various 

 methods used by potters for determining the tempera- 

 ture of their kilns, a long account is given of Wedg- 

 wood's pyrometer, Seger cones, and all the later 

 forms of electrical pyrometers, including the Fdry 

 radiation pyrometer, but there is no adequate dis- 

 cussion of the relative value of these different methods 

 in the actual working of a pottery, the observations 

 on the employment of pyrometers (pp. 257-261) being 

 simply a one-sided account of the merits and demerits 

 of Seger cones. 



The second half of the book contains a reasonably 

 detailed account of the processes of manufacture, 

 firing, glazing, and decoration of bricks, tiles, terra- 

 cotta, refractory pottery, stoneware, earthenware, and 

 porcelain. Again the method is excellent, but, of 

 course, too much has been attempted, and it seems 

 obvious that the student would have been better 

 trained or assisted by a more complete treatment 

 of one or two sections only. From the English 

 point of view, the greatest failure of the book is 

 the ignorance shown of actual English methods 

 in those branches of pottery manufacture where 

 this country is supreme. Thus the account given 

 of the manufacture of English earthenware is 

 not merely incomplete, but is full of misappre- 

 hensions — even of mistakes. The mixtures said to 

 be used for English bodies and glazes are such as no 

 first-rate potter would dream of using ; the description 



