1917] AGRICULTURAL CHEMISTRY AGROTECHNY. 803 



oils; special characteristics of essential oils; tannins; analysis of leather; 

 analysis of coloring materials ; coloring matters of natural origin ; coloring 

 matters in foods ; printing inlis ; inks ; amins and ammonium bases ; anilin and 

 its allies ; tlie naphtylamins and their allies ; the vegetable alkaloids ; volatile 

 alkaloids ; estimation of nicotin ; aconite alkaloids ; atropin and its allies ; 

 cocaine ; opium alkaloids ; strychnos alkaloids ; cinchona alkaloids ; berberin and 

 its associates; caffein, tea, and coffee; other vegetable alkaloids; glucosids; 

 nonglucosidal bitter principles ; animal bases ; animal acids ; lactic acid ; 

 cyanogen and its derivatives ; enzyms ; proteins ; vegetable proteins — flour ; 

 proteins of milk ; milk products ; albuminoids ; meat and meat products ; 

 fibroids ; and an appendix. 



A complete author and subject index of the entire work is included in the 

 volume. 



Hew apparatus for colorimetry, E. Moreau (Afin. Falsif., 10 {1911), No. 

 103-104, pp. 235-237, fig. 1). — A simple apparatus for routine analysis and its 

 manipulation are described. It consists essentially of two colorimetric tubes, 

 to one of which is attaclied at its lower end a piece of rubber tubing which is 

 connected to a leveling bulb. This tube is used for the standard color solution, 

 and by this arrangement the volume can be readily changed until the color cor- 

 responds with that of the unknown sample. 



The calculation of the results is described. 



Discontinuous extraction processes, L. F. Hawley {Jour. Indus, and Engin. 

 Chem., 9 {1911), No. 9, pp. 866-871). 



A simplified microcombustion method for the determination of carbon and 

 hydrog-en, L. E. Wise {Jour. Amer. Chem. Soc, 89 {1917), No. 9, pp. 2055-2068, 

 figs. 4)- — A modification of the Pregl ^ microcombustion method for the deter- 

 mination of carbon and hydrogen, in which 11- to 22-mg. samples are used 

 and which does not require the use of a microbalance, is described. A sensi- 

 tive analytical balance has been found to yield satisfactory results. The 

 drying train of the original method has been modified, and the technique used 

 in weighing and in carrying out the combustion has also been modified and 

 standardized. 



Analytical data obtained in the combustion of pure substances containing 

 carbon, hydrogen, and oxygen indicate that the accuracy of the micromethod is 

 comparable to that of the ordinary macrocombustion. Preliminary data in- 

 dicate that the procedure, without furtlier modifications, may be applicable to 

 . the microanalysis of a variety of nitrogenous organic compounds. The limita- 

 tions and possible applications of the method are briefly discussed. 



The possibilities and limitations of the Duclaux method for the estimation 

 of volatile acids, L. J. Gillespie and E. H. Walters {Jour. Amer. Chem. Soc. 

 S9 {1917), No. 9, pp. 2027-2055, figs. 3).— The authors have studied the Duclaux 

 method in detail and have stated and verified the laws which must be assumed 

 to calculate the results of analyses. Algebraic and graphic methods for the 

 computation of results for mixtures of two or three acids have been described 

 and the algebraic calculation for four or more acids indicated. Application of 

 the methods to known mixtures shows that mixtures of two or three acids may 

 be quantitatively analyzed without too great error. The errors, however, are 

 in general too large for mixtures of four acids. 



Data obtained show that the errors of the method are not proportional to 

 the quantities of acid present. Mixtures containing four or more acids in 

 significant quantities must be fractionated before applying the method into 

 mixtures containing only three acids. " In order to apply the Duclaux method 



« [Abderhalden's] Handb, Blochem. Arbeitsmethod., 6 (1912), pt. 2, pp. 1307-1356. 



