April 30, 1896] 



NA TURE 



603 



quite sincere, it must be admitted that every detail in 

 respect to electrical developments is an evolution. It is 

 in this way that electricity has progressed and will con- 

 tinue to progress, that is to say, on the bare data pro- 

 pounded by one man another will proceed. The one will 

 modify experiment ; will get an advanced result, and 

 from his result the next man will take up the parable 

 and will progress. Thus, though there may be a thousand 

 discoveries in electricity, there will never be one prophecy; 

 and if Dr. Benjamin's book exposes this startling truth, 

 it has performed a duty which probably its author did 

 not expect of it, and for which the world will be grateful. 



ARTIFICIAL COLOURING MATTERS. 



%Trat/e des Matiires Col or antes organiques artificielles., 



% de leur preparation indiistriclle et de leurs applications. 



e Par Leon Lefevre. Two vols. Pp. xx + 1648. (Paris : 



« G. Masson, 1896.) 



jTN the early days of the coal-tar colour industry the 

 -»- French chemists. Coupler, Lauth, Girard and De 

 Laire, and others did good work in the way of investiga- 

 tion, and certain standard books of reference which were 

 indispensable in their time bore the names of French 

 authors. Then the centre of activity in this field seems 

 to have been shifted to Germany, and for some years we 

 have been accustomed to look to that country for new 

 discoveries and authoritative treatises. The author of 

 the work now under consideration, M. Leon Lefevre, who 

 is " Preparateur de Chimie" in the Ecole Polytechnique, 

 has once again set the current of coal-tar literature flow- 

 ing in France, and he is to be congratulated on having 

 produced a treatise which may, without exaggeration, be 

 described as the most comprehensive that we have at 

 present in any language. The two bulky volumes under 

 notice cover the ground occupied by several distinct 

 German works; for not only is the subject dealt with in its 

 purely chemical aspect, but the methods of production on 

 the large scale, and the modes of application of the 

 various colouring matters are likewise given in detail. It 

 is impossible in these columns to give a critical review of 

 a technical work of this magnitude, but a general state- 

 ment of the method of treatment will enable those who 

 are interested in the subject to form an idea of the extent 

 to which they are indebted to M. Lefevre. 



The colouring matters are classified into groups in 

 accordance with the scheme originally adopted by Nietzki, 

 and now. familiar to all chemists who are acquainted 

 with this- bcanch of their science. Each group com- 

 mences with a preliminary statement setting forth the 

 history, general characters and constitutional formula? of 

 the compounds dealt with ; then follows the description 

 of the individual colouring matters, and afterwards a 

 tabular summary of the whole group, from which can be 

 seen at one glance the mode of preparation, the formula, 

 the commercial name, the appearance and properties, 

 and the references to the literature, patent or otherwise. 

 Following these extremely valuable tables, there is a 

 section on the technique, i.e. the method of manufacture, 

 the processes being described in sufficient detail to be 

 of value to technologists, and the plant being figured by 

 ■well-executed cuts. The reader having thus been led 



NO. 1383. VOL. 53] 



up from the history of the discovery of the colouring 

 matters to their production on the large scale by the 

 latest and most approved methods, is then let into the 

 mystery of the dyer's art, and is given explicit directions 

 how each colouring matter should be applied as a 

 tinctorial agent. With each group there is also associated 

 a tabular scheme of the diagnostic reactions of the 

 colouring matters on the fibre, a list of bibliographical 

 references, and lists of patents. 



It does not often fall to the lot of the reviewer of a tech- 

 nical work to be raised to an enthusiastic state of mind by 

 the treatise which has been submitted to his judgment ; 

 but in the present case, it was certainly with something 

 akin to enthusiasm that we turned over the pages of 

 M. Lefevre's luxurious volumes. The synopsis of the 

 mode of treatment which we have attempted to give will 

 show that in one work we now have the chemistry of the 

 coal-tar colouring matters on the lines adopted by Schultz 

 in his well-known treatise of 1887-90, the tabular synopses 

 made familiar by the tables of Schultz and Julius, edited 

 by Green in 1894, the technique of manufacture for which 

 we have had to refer to such works as that by Miihlhauser, 

 the tinctorial characters and modes of application for 

 which we have been in the habit of consulting special 

 treatises on dyeing and printing, and lastly, the diagnostic 

 reactions which are generally looked up in some work on 

 proximate organic analysis. To say that the author has 

 covered all this ground in a perfectly faultless manner 

 would be to attribute to him superhuman faculties ; but, 

 with the exception of a few doubtful statements of history, 

 we are bound to say that no serious flaw is to be found in 

 the 1648 pages composing the work. The dyed and 

 printed patterns on wool, silk, leather and paper, of 

 which there are over 260 specimens, make the volumes 

 somewhat ungainly, and would perhaps have been better 

 collected together into a distinct supplementary volume. 

 The thirty-one illustrations of plant are executed with 

 that clearness for which our French colleagues are so 

 justly celebrated, but, as is so generally the case, they 

 suffer from the defect of having no scale of size attached. 

 The structural formula: occupy a very much largerlamount 

 of space than we are accustomed to here, owing to the 

 free use of the benzene hexagon, but this is a matter of 

 luxury and not a point for critical complaint ; it must, 

 however, have added considerably to the cost of printing. 



The work is introduced to the public by a preface ^fom 

 the pen of M. Edouard Grimaux, Membre de I'lnstitut, 

 who at the close of his remarks says : — 



" En raison de I'interet que je porte k I'auteur, mon 

 fidele corapagnon de laboratoire depuis dix ann^es, il me 

 serait difficile de faire I'doge de son livre et de dire tout 

 le bien que j'en pense ; mais j'ai vu naitre et continuer 

 cet ouvrage sous mes yeux, et je puis t^moigner de la 

 conscience avec laquelle il a et^ fait ; j'ai tout lieu 

 d'esp^rer qu'il recevra du public savant I'accueil qu'il 

 mdrite." 



The commendation which M. Grimaux modestly with- 

 holds may be supplied by this notice ; and in directing the 

 attention of English chemists to M. Lefevre's treatise, we 

 have not the least hesitation in stating that the author 

 has succeeded in producing a coal-tar classic which must 

 take precedence over every other work on the subject. 



R. Meldola. 



