NATURE 



497 



THURSDAY, OCTOBER ii, 1877 



FLEISCHER'S " VOLUMETRIC ANALYSIS" 

 A System of I olumctric Analysis. By Dr. Emil 

 Fleischer. Translated by M. M. Pattison Muir, 

 F.R.S.E. (Macmillan and Co., 1877.) 



THERE is no question that volumetric analysis does 

 not yet play that important part in quantitative 

 chemical analysis which it merits, and which on the 

 appearance of Mohr's well-known ''Titrirmethode" it was 

 confidently anticipated that it would assume. The 

 method of instruction commonly pursued in many of our 

 large public laboratories is in a great measure to be blamed 

 for this result. It is, of course, necessary that the student 

 should be put through a thorough course of gravimetric 

 analysis, in order that he may attain that manipulative 

 dexterity without which he cannot hope to become a 

 successful operator, and perhaps no branch of practical 

 chemistry is better calculated to afford the requisite 

 training and practice than the somewhat tedious process 

 of weight analysis, with its innumerable separations, 

 flltrations, washings, and weighings. But however 

 excellent may be their educational value, and however 

 accurate their results, there is no doubt that many of the 

 gravimetric methods at present in common use when 

 viewed as practical processes for every-day application, 

 fall very far short of what is required of them. It not 

 unfrequently happens that the busy chemist, uncertain 

 whether a lengthy analysis will afford him, after all, the 

 requisite information, hesitates to incur what he fears may 

 turn out to be a useless sacrifice of valuable time, and 

 hence, from the want of rapid and sufficiently accurate 

 analytical methods, many weighty facts may have been, 

 doubtless actually have been, overlooked. Indeed, it is 

 a question whether some of these analytical processes 

 have not done as much to retard the progress of chemical 

 science as to advance it. The majority of chemical 

 workers, especially these engaged in scientific research, 

 have not made analysis a special study, and hence when 

 they are under the necessity of making a particular 

 determination, they are content with the time-honoured 

 processes which they have learned in the course of their 

 laboratory-training. It is only by the appearance of such 

 works as the one before us that the greater number of 

 chemists are made aware of the advances which 

 quantitative chemistry has really made. 



^Ir. ?\Iuir has done a very considerable service to his 

 chemical brethren by his translation of Dr. Fleischer's 

 work, for if we are not mistaken, it is the first attempt at 

 a radonal system of volumetric analysis which has been 

 offered to us in this country. The work is divided into 

 three distinct parts. In Part I., which treats of the 

 volumetric method, we have, in Section I., an account of 

 the principles on which this branch of the art of analysis 

 rests. The several forms of burettes, pipettes, and mea- 

 suring flasks recommended by the author, are described, 

 together with the methods for their calibration and verifi- 

 cation. The modes of preparing and standardising the 

 normal solutions are next described. Section II. treats 

 of the ordinary alkalimetric and acidimetric processes. 

 Section III. gives an account of the various methods 

 Vol. XVI.— No. 415 



depending upon oxidation and reduction ; these are respec- 

 tively design::ted as oxidimetric and iodometric methods. 

 Lastly, in Section IV., we have a description of the more 

 important precipitation methods, e.g., Mohr's method of 

 determining chlorine by standard silver solution, and 

 Wildenstein's process for estimating sulphuric acid by a 

 standardised solution of potassium chromate. There is 

 little in this part which calls for special remark ; we 

 would, however, point out that in the discussion on 

 experimental errors, the magnitude of which, as the 

 student is vaguely informed, may in certain cases be 

 calculated by the mathematical method of least squares 

 it is not very apparent from the description how certain 

 of the errors are eliminated. Dr. Fleischer's language 

 is either not very clear on the subject, or his translator 

 has failed to catch its exact meaning. The account of a 

 method of verifying a pipette given on p. 23 will be apt 

 to puzzle a beginner, on account of the unfortunate con- 

 fusion between burette and pipette. We fail to see the 

 necessity for the retention of the Rdaumur scale of tem- 

 perature in a work intended for English readers ; and we 

 are constrained to protest, with all possible energy, 

 against the introduction of a new standard of tempera- 

 ture. What particular significance has I4°'5 R. to us in 

 this country .' If we are not content to take the melting- 

 point of ice or the point of maximum density of water 

 as our standard, let us at least maintain our credit as a 

 law-abiding people by conforming to the enactments of 

 our Legislature. In these respects Mr. Muir has un- 

 doubtedly sacrificed his independence to his loyalty to his 

 author. 



Unquestionably the most distinctive feature of the work 

 is seen in Part II. ; indeed, this constitutes a most valu- 

 able addition to the art of chemical analysis. In this part 

 the author describes a variety of volumetric processes by 

 means of which a large number of acids and bases may 

 be determined, either separately or when mixed. He has 

 not attempted to describe all the methods which have 

 been proposed for the determinations of the several con^ 

 stituents, but has given only those which he has himself 

 found to be reliable and capable of general application. 

 In Section II. of this part it is shown how each base may 

 be determined by volumetric methods without previous 

 group-separation. The substance to be analysed is ob- 

 tained in solution by the appropriate methods (which are 

 fully described), and is divided into as many portions as 

 there are constituents to be determined. As the author 

 tells us, " the process of analysis is thus much shortened, 

 not only by the omission of group-separations, but also 

 by the fact that but one or two flltrations at the most are 

 necessary ; in many instances no flltrations are required. 

 The precipitates do not require the same long-continued 

 washing which consumes so much time in the ordinary 

 processes. Two circumstances more especially recom- 

 mend the methods under consideration. Every estima- 

 tion is readily controlled by repeating the process on the 

 original liquid ; the analyses of technical products in 

 which one or more, but not all, of the constituents is to 

 be detennined, becomes a matter of ease, and can be 

 carried out much more rapidly than when it is necessary 

 to make a systematic separation of the metallic groups.' 

 Lastly, in Part Ill.it is shown how these methods are 

 applied to the analysis of a number of important techni- 



