REVIEjWS 



New Reduction Methods in Volumetric Analysis. By E. Knecht and 

 E. Hibbert. [Pp. x+108.] (Longmans, Green & Co. Price 3^. net.) 



The cult of the Text- Book has been so developed of late and such large numbers 

 of students are little short of stupefied by this form of literature at the present day, 

 that any book departing from current forms and showing evidence of independence 

 is exceptionally welcome. That under review, in the first place, is to be 

 commended for its originality of subject. Possibly the authors of so modest 

 a volume realised that about a quarter of a century must elapse ere any new 

 methods would find place in the established Text-Books and therefore decided 

 to compile their own monograph upon the subject. 



It is now more than nine years since the use of titanous chloride as a 

 quantitative reducing agent was first recorded ; since then a considerable amount 

 of work has been done showing that the use of this substance is of very general 

 application. 



The lack of suitable reducing agents unfortunately has prevented the develop- 

 ment of volumetric methods of analysis based upon reduction processes. The 

 authors are to be congratulated upon the part they have played in developing the 

 methods of using titanous chloride in quantitative analysis, as well as for having 

 brought together in practical form the records of work on this subject which 

 have been scattered over a number of years and which have appeared in various 

 journals. The collected information is presented in a form both clear and concise : 

 chief interest, however, centres around the novelty of the methods rather than 

 upon a real advance in accuracy or convenience in the estimations. Had a 

 comparison been made of the results obtained by the usual methods with those 

 obtained by the new methods described and had the authors discussed the 

 advantage of these new methods over those usually adopted, the value of their 

 book would have been greatly enhanced. As it is, there is little to convince the 

 reader that the methods described are in any way superior to those generally 

 adopted in the laboratory : for example, it might well be doubted whether any 

 advantage would accrue from estimating the copper in the filtrate from a reduction 

 of Fehling's solution by glucose rather than by proceeding in the usual way to 

 reduce the collected precipitate of cuprous oxide and weigh or titrate the copper. 

 Although similar arguments apply to other cases, there are many in which the use 

 of titanous chloride becomes advantageous. 



In carrying out some of the operations described a considerable amount of 



dexterity and practice is required but this should not deter those who would make 



use of the methods from essaying their hand, because consolation is to be found 



in the last paragraph of the Preface, where an assurance is given that second-year 



students are quite able to carry out the operations involved in the new methods 



of analysis. 



J. V. Eyre. 



496 



