410 



NA TURE 



[September 3, 1896 



vindicate the claims of Columbia College to that rank, 

 and to secure for it increasing repute and public use- 

 fulness. He urged on the Trustees the importance of 

 making the College available for the advanced education 

 of women, and succeeded after long and arduous effort 

 in establishing what is now known as the Barnard 

 Annexe to the College, a feminine institution practically 

 under the care of the same professors, and aiming at 

 the same academic course. In 1882 he took the first 

 steps in a movement with which the name of Dr. Murray 

 Butler has since been conspicuously associated for estab- 

 lishing a professorship in the literature, history, and art 

 of Education, and for securing professional training for 

 those students who intended to become teachers. On 

 the whole the book, though diffuse in style and en- 

 cumbered with some needless detail, is a useful con- 

 tribution to educational history. It is the record of a 

 strenuous and honourable life, of high and generous aims 

 often obscured by discouragement, but ever kept steadily 

 in view, and of a considerable number of experiments, 

 both in regard to instruction and discipline, which have 

 done much to render the solution of educational problems 

 easier, especially in America. J. G. Fitch. 



APPLIED 



CHEMISTRY OF NITRO- 

 EXPLOSIVES. 



Nitro- Explosives. By P. Gerald Sanford, F.I.C., F.C.S. 

 Pp. xii + 270. (London : Crosby Lockwood and 

 Sons, 1896.) 



WE had lately under our notice a work on explosives 

 which dealt with their manufacture more from an 

 engineer's point of view than from that of a chemist, 

 and consequently the various appliances were described 

 with a detail which only a practical engineer could pro- 

 perly express. In the present volume the processes are 

 placed before us exclusively from a chemist's point of 

 view, and the appliances and machines used receive 

 generally but a brief notice ; indeed, some fifty sketches 

 is the sum total of the illustrations covering the ap- 

 paratus used in the manufacture of the numerous nitro- 

 compounds touched upon in the book. Of these sketches 

 a considerable number are of different pieces of chemical 

 apparatus made use of in testing the raw or finished 

 material. 



The author first briefly considers some of the chemical 

 groups from which the nitro-compounds are formed, and, 

 in doing so, volunteers the statement that " the nitro- 

 explosives belong to the so-called High Explosives." 

 This, however, depends very much on whether these 

 explosives are intended to be used as disruptive agents 

 for producing local effect, or as propelling agents. In 

 other words, taking Hess's definition, a high explosive 

 is one which requires the use of a detonator to develop 

 its full value, as with guncotton or dynamite ; a low 

 explosive, as gunpowder, does not require a detonator, 

 but will exert its full power by simple ignition. Here 

 again, however, we require to make some qualification as, 

 although all the nitro-explosives are high explosives in 

 one sense, it depends on whether they can, or cannot, be 

 detonated in order that we may define them as high 

 explosives pure and simple, or as explosives of high 

 NO. 14OI, VOL. 54] 



energy. Practically speaking, only the latter are suit- 

 able for propelling or ballistic purposes, while the former 

 class should be used as blasting agents only. An ex- 

 plosive which can be detonated by a detonator, can also, 

 by suitably confining it, be often exploded by a simple 

 ignition in such a manner that its explosion really 

 becomes a detonation, or partakes of the nature of a 

 detonation, i.e. very high local pressures are developed. j 

 It is, therefore, a matter of considerable importance to | 

 definitely ascertain that explosives to be used as ballistic " 



agents cannot be detonated. 



The chief value of the book depends on those por- 

 tions dealing with the manufacture of nitro-glycerine, 

 dynamite, and guncotton, and the testing of the raw 

 and finished material. The descriptions relating to these 

 explosives show very evidently that the author has per- 

 sonally participated in their manufacture, and his remarks, 

 which are generally to the point, are consequently of 

 considerable value to chemists and others engaged in 

 similar operations. Mr. Sanford very properly lays much 

 stress on the testing of the materials used in all the 

 stages of manufacture, and it will be found that nearly 

 as much space has been devoted, in different parts of 

 the book, to testing and analysis as to the actual manu- 

 facture of the explosives. Unfortunately, the reader is 

 credited with being already more or less familiar with the 

 appliances connected with the manufacture of explosives, 

 and therefore the author apparently considers that a brief 

 notice is all that is necessary. Nitro-glycerine and nitro- 

 cellulose have, however, become so important in connec- 

 tion with civil and military undertakings, that those who 

 employ such explosives are glad to be able to read an 

 interesting account which is trustworthy without being ex- 

 haustive, and which does not make too great a demand on 

 the pocket. To such this book is especially recommended, 

 as these substances receive the greatest share of attention, 

 and they form the basis of the more powerful and popular 

 blasting materials, and also of practically all the smoke- 

 less powders used in small arms or artillery ; but, besides 

 these uses, nitro-cellulose (collodion-cotton) is employed 

 to a very large extent in the production of that most 

 useful material called celluloid, xylonite, or imitation ivory, 

 of which so many articles of every-day life are made, 

 such as knife-handles, buttons, photographic dishes, and 

 billiard balls. The manufacture of this substance forms 

 one of the most interesting portions of the book, and, 

 although not properly coming under the category of an 

 explosive, it finds a fitting place in this work. 



It must not, however, be forgotten by those who make 

 use of celluloid that it becomes, under certain conditions, 

 a powerful explosive. Celluloid shavings also should 

 never be allowed to accumulate, as they take fire easily 

 at a comparatively low temperature, and, in this state, 

 burn with surprising rapidity. 



In the analysis and testing of explosives, to which, as 

 we have stated above, due prominence has been given, 

 the various operations are briefly but concisely explained. 

 They are evidently written for the use of practical 

 chemists, and will, no doubt, be duly appreciated by them. 

 With regard to the heat or stability test which is applied 

 to most explosives before they are passed for service, it 

 has lately been put beyond doubt that the sun's rays 

 have a marked effect on some explosive substances. 



