538 



NA TURE 



[October 7, 1897 



silver, as the quantity deposited by the passage of the 

 quantity of electricity which is to be taken as unity, loses 

 the air of arbitrariness it must at first sight have to many 

 readers of Prof Ayrton's book. 



The order more usually followed in this matter is also, 

 quite as much as the other, in the spirit of the plan of 

 giving in a treatise on electricity initial prominence to 

 the electric current and its effects. We may remark, 

 though not with reference to anything stated by Prof. 

 Ayrton, that in a good deal of the talk about beginning 

 at this point or that in an exposition of electrical matters, 

 it seems to be forgotten that some previous discussion 

 of elementary magnetic, or it may even be electric 

 phenomena, is desirable and even necessary. To quite 

 understand the action of a current on a magnet, it is 

 necessary to know something about magnets and mag- 

 netic fields. The truth is that, in a system logically 

 consistent, as the science of electricity to a very great 

 extent is, the point of attack is very much a matter of 

 convenience. It is possible, of course, and it is done in 

 some recent .discussions, to begin with Maxwell's or 

 Hertz's equations for electromagnetic action, and work 

 round to electrostatic action as a mere residual effect. 

 Still, in all such exercitations, a great amount of previous 

 knowledge is taken for granted. The teacher has a 

 difficult task in any case, for he soon finds in whatever 

 way the discussion is undertaken, that to know one 

 thing with approximate completeness it is necessary to 

 know everything else. The study is a process of gradual 

 approximation to clear and accurate conceptions, and if 

 this were more recognised, there would be less dis- 

 couragement of some students, and on the part of others, 

 less cocksureness and contempt of what does not excite 

 their interest, or is only capable of discussion by 

 methods which have the misfortune to meet with their 

 disapprobation. 



A very important section of the book before us is that 

 which deals with the power developed in the circuit of a 

 generator, the conditions for the evolution of the maximum 

 power in the working part of the circuit, electrical and 

 commercial efficiency, and the transmission of power. 

 The thorough practical study of all these questions 

 which Prof Ayrton has made invests this part of the 

 book with a special interest and authority. Nothing 

 could be clearer and better illustrated by graphical ex- 

 hibition of the results, and by practical examples, than 

 this long chapter. Perhaps a somewhat more explicit 

 warning might have been added with regard to the fallacy 

 which people apparently will fall into of confusing the 

 arrangement of maximum power with that of maximum 

 efficiency. -Of course the discussion of efficiency ought to 

 bs sufficient to guard against error ; but we have not seen 

 the last yet of what at one time seemed inveterate, the 

 continual misapplication of the so-called law of Jacobi. 



Of the chapter on cells, &c., we will only say that 

 it is in moderate compass a veritable store of .information, 

 which would only be found with difficulty, if at all, after 

 much searching of other books, and to ordinary students 

 more or less inaccessible papers. 



By completing the book Prof. Ayrton will confer a 

 further great benefit on all students of electricity, 

 technical or otherwise ; and we hope the second volume 

 will not be long delayed. A. Gray. 



NO. 1458, VOL. 56] 



PRIMITIVE FRENCHMEN. 

 Formation de la Nation Franqaise. By Gabriel de 

 Mortillet. With 153 engravings and maps in the 

 text. (Paris: F. Alcan, 1897.) 



THE account which Prof de Mortillet gives of the 

 formation of the French nation is based upon 

 archaeological data. It is true that he depends on anthro- 

 pological materials, but these are prehistoric, and therefore 

 archaeological. The anthropological investigations on 

 modern Frenchmen by Broca, Topinard, and others 

 have been neglected ; even the brilliant researches of 

 Collignon are not referred to. The book thereby loses 

 somewhat in breadth, and the linkage of the past with the 

 present, which the author so firmly appreciates, would 

 have been brought home more forcibly to the general 

 reader if these investigations had been summarised. 



The author first. shows that the Bible, legends, ancient 

 texts, and even linguistics, are too untrustworthy to deter- 

 mine the origin of any people ; reliance must then be 

 placed on anthropology and palethnology, including 

 archaeology. The three terms, race, language, and 

 nationality, are discussed clearly and tersely. Race is 

 an anthropological fact and implies common descent, 

 the prolonged action of environment or complete fusion 

 of various primitive elements. Numerous examples, 

 illustrated by maps, are given to show that the distribu- 

 tion of race and language are by no means identical. If 

 Germany claims Alsace because the population speaks 

 German, why does she retain French-speaking Lorraine ? 

 Nationality is a sentiment, and is not based on racial but 

 on sociological reasons. The first half of the book deals 

 with historical documents. The ethnic and geographical 

 discrepancies of various classical authors are pointed 

 out ; few had any personal acquaintance with the people 

 and places they described, and most of them romanced. 

 Practically all agree in describing the Celts or Gauls and 

 the Germans in the same terms. Tall, fair people, with 

 blue eyes, white skin, very warlike, and readily under- 

 taking great invasions and vast migrations, constructing 

 neither temples nor towns, fighting naked, but very proud 

 of their hair. But below this military aristocracy there 

 were the common people, ignored by the writers, who 

 constituted the patient and laborious democracy fixed to 

 the soil, the true natives of the country, whom anthropo- 

 logy and palethnology have revealed. The Gallo-Ger- 

 manic race is spread over nearly the whole of Europe, 

 and extends into Africa and Asia, each band transport- 

 ing its particular name to the different countries that it 

 occupied. 



The languages of France are next dealt with. The 

 remarkable agglutinative Basque language is briefly dis- 

 missed, as are also the " Celtic " dialects. " The language 

 spoken in Gaulbefore the Roman conquest is unknown by 

 us." Various early inscriptions and prehistoric carved 

 stones are briefly reviewed ; the latter are classified 

 under (i) simple decorative motives; (2) conventional 

 and commemorative carvings ; (3) symbolic carvings^ 

 very difficult to understand, but apparently not alpha- 

 betical. No reference is made to the remarkable painted 

 stones from Mas-d'Azil. 



The third section of the book is devoted to paleth- 

 nology. Tertiary man is discussed. Mortillet admits 



