AGRICULTURAL CHEMISTRY — AGROTECHNY. 115 



Akad. Hnndl och Tidskr.. J/D [li)10). Xo. J. pp. 77-7'.'/). — This method, originally 

 proposed by M. Weibull (E. S. li., 9, p. 224). involves the determination of the 

 total solids and the calcnlation of the percentage of fat by difference, it being 

 assumed that the average cream contains 8.7 per cent of fat-free solids. The 

 author suggests determining the total solids (0 by a method similar to that 

 now used for the water content of butter in creameries. About S gm. of 

 cream is to be weighed in a small creamery balance and the dish carefully 

 heated over an alcohol lamp, stirring constantly during the operation until 

 the mass assumes a light brown color, when the dish is to be allowed to cool and 

 again weighed. The fat content (/) is calculated from the formula /=!. 1^—9.5. 



The results obtained by this method agree within 0.2 per cent with the gravi- 

 metric method. A table is appended showing the percentages of fat in cream 

 correspoiHling to the different percentages of solids. 



Examination of cream, O. Lobeck {ilolk. Ztg. [Hlldcsheim], 24 {1910), A'o. 

 IS, pp. 215-218). — A comparative study of methods, with particular reference 

 to the utility of the Sal-method. 



The newer methods for testing butter and margarin, J. Prescheb (Phavm. 

 ZeiitraUiallc, 51 (1910), No. 7, pp. 12S-127). — This is a discussion of the newer 

 methods for examining butter, margarin, and mixtures of margariu and butter 

 and other fats. Analyses ;ire appended to illustrate the various points taken up. 



A color reaction for butter and lard, C. Keichard {Phunn. ZcnfniUiolJc, 51 

 (1910), A'o. 6', p. 107). — It was observed that when finely powdered copper sul- 

 phate was added to melted butter and melted lard the butter assumed the green 

 color of the copper salt and the lard did not. The color became intense on 

 standing after being exposed to the air for some time. 



A modified Uffelmann reaction, H. Kxjhl (Pharm. Ztg., 55 (1910), No. 12, 

 pp. 120, 121; ahs. in Molk. Ztg. [HUdcshciiii], 2', ( 1910), No. 16, p. 276).— The 

 author draws attention to the fact that the Uffelmann test also reacts with 

 oxalic, tartaric, succinic, and citric acids. It is proposed to consider it a group 

 reaction and to modify the test as follows : To 10 cc. of a cold saturated solu- 

 tion of salicylic acid add a few drops of ferric chlorid, and then a few drops of 

 the solution to be tested foj* lactic or the other acids. If these are present a 

 yellow color ensues. The reaction thus modified is much more sensitive than 

 the original one with phenol. 



Brewers' grains, M, Gonnermann (Ztschr. Offentl. Chem., 16 (1910). No. 3, 

 PI). .'il--'i5). — This is a discussion in regard to the identity of the substances in 

 brewers' grains which cause a right-hand rotation. Tests were made with 

 alcoholic and aqueous extracts and the results led the author to conclude that 

 the substance extracted by alcohol is maltose and that that extracted with water 

 is practically erythrodextrin. Special stress is laid on the importance of de- 

 termining the invert sugar and analyzing according to Clerget's method when 

 examining I)rewers' grain molasses feeds. 



Schaffnit's method for determining impurities in linseed press cake, J. A. 

 EzKNDAM {Lcindir. ^'(•rs. .S'/fl^, 71 (1909). No. '/-o. pp. 2.S7'-?.0,S ) . — This is a com- 

 parative study between the Sehaffnit method," modified by the author, and the 

 Netlierland method. It is concluded that the Netherland method is to be pre- 

 ferred. 



Estimation of the acidity of apple must, C. Brioux (Cidre et Poire, 1909, 

 p. 229; rt&.s. in Ann. Falsi/., 3 (1910), No. 16, p. 72).— Twenty cc. of the must 

 are placed in an alkalimeter and 5 cc. of sodium bicarbonate solution added. 

 Erom the difference in weight due to the evolution of carbon dioxid the acidity 

 may be calculated as malic acid. 



"I.audw. Vers. Stat., 67 (1907), pp. 51-56. 



