1919] AGRICULTURAL ( 1 1 KM ISTRY — AGROTECHNY. 807 



duction of the platinum t<» platinum black. The distillate is Creed from acetal- 

 dehyde i>y distillation with a reflux condenser, the temperature being s<> regu- 

 lated that the acetaldehyde passes out through the top of the retlux condenser 

 into a delivery tuhe connected with a coil condenser and the alcohol drops hack 

 Into the distilling flask. A few pieces of sodium hydroxid are then added to the 

 distilling ilask and the alcohol distilled until a specific gravity of 0.8045 is 

 obtained. 



A sensitive copper reaction. — Application to the analysis of ash and of 

 arable soils, L. Maquknnk and B. Dkmoussy (('ompt. Rcn<l. Acad. Sci. [I'urix], 

 168 (1919), No. 10, pp. 489-492). — A method of determining minute amounts of 

 copper is described, the technique of which as applied to the analysis of the 

 ash of grains and of soils is as follows: 



The material is ashed in a quartz crucible in the presence of a few drops of 

 nitric acid and a slight excess of sulphuric acid. From 0.05 to 0.2 gm. of the 

 ash is mixed with 1.5 cc. of 5 per cent sulphuric acid, and kept at boiling tem- 

 perature for 20 minutes to transform the pyrophosphates to orthophoaphates. 

 It is then washed into a small tube, centrifuged to separate the particles of 

 silica and calcium sulphate remaining in suspension, and the liquid, the volume 

 of which should be about 2.5 cc, subjected to electrolysis. After 12 hours the 

 cathode is washed with 3 drops of hot nitric acid and a little water, and the 

 solution is evaporated, ashed, taken up with 3 drops of hydrochloric acid, and 

 washed into a tube. The total volume of liquid at this point should not exceed 

 2 cc. To the solution are added 2 drops of a 1.104 per cent solution of zinc sul- 

 phate and 1 drop of a freshly prepared 10 per cent solution of potassium ferro- 

 cyanid. If the copper is abundant, there appears immediately a rose color, 

 which changes to blue on shaking the tube. If less than 0.00001 gm. of copper 

 is present, the blue color appears only at the end of several minutes. 



The necessity is pointed out of using quartz or porcelain crucibles instead of 

 platinum and of running blanks to prove the absence of copper in the reagents 

 employed. 



The content of copper in various seeds as wheat, corn, peas, beans, etc., has 

 been found by this method to be between 3 and 8 mg. per kilogram, and that of 

 certain arable soils from 2 to 30 mg. per kilogram, which allows the determi- 

 nation to be conducted on as small an amount as 5 gm. of the soil. 



Estimation of the water content of meat products and sausages, E. Seel 

 (Ztaohr. I'ntcrsuch. Nahr. v. Genussmtl, 35 (1918), No. 11, pp. 393-411). — The 

 author discusses the use of Feder's proportionate number (the ratio of the 

 estimated water to organic material not fat) as a means of estimating the water 

 content of meats, and states that it can be used to determine the amount of 

 water in minced meat or in sausages which are made from lean meat without 

 the addition of fat or other kinds of meat. 



Judging buttermilk porridge. J. D. Filippo (Chan, Wcckbl.. 16 (1919), No. 

 2, pp. 41-44)- — The author describes a buttermilk porridge which has recently 

 come into use in Holland, and outlines a method to detect adulteration or the 

 use of buttermilk of doubtful composition. 



The porridge is made by treating oats or wheat with warm water or steam to 

 the required consistency and then warming with buttermilk. According to the 

 Codex Alimentarius 1 liter of the porridge should contain no less of the con- 

 stituents of buttermilk than are found in 0.8 liter of true buttermilk. 



The constants considered of greatest value are the amount of casein and the 

 rotatory power, methods of determining which are described. The standard 

 porridge should contain not less than 1.8 per cent casein and have a specific 

 rotatory power of not less than 2.7 per cent 



