712 



SCIENCE. 



[N. S. Vol. XXIII. No. 592. 



by this method the acidity has only been re- 

 duced about half. On the other hand, the 

 acidity of plot 24 to which ammonium sul- 

 phate has been applied is materially increased, 

 but Dr. Thorne writes me that the red cloTer 

 grown on this plot is not visibly less than 

 that grown on nearby plots to which nitrogen 

 in linseed meal or dried blood was applied. 



No explanation can be offered at this time 

 of the behavior to both methods of plots 8 and 

 19 limed. 



It appears then that while sodium nitrate 

 and basic slag have diminished acidity, no fer- 

 tilizer or combination of the fertilizers used 

 has measurably increased acidity on this soil 

 except where ammonium sulphate was applied. 

 We can not apply this conclusion, however, to 

 soils of different character. While the acidity 

 due to the residue left by the taking up of 

 plant food may reasonably be supposed to be 

 irrespective of the nature of the soil, the acidity 

 produced by decomposition reactions between 

 the soil components and added salts is not. 

 While in this soil the attack of neutral salt 

 solutions upon what I have elsewhere called 

 ' non-acid silicates ' is small, with other soils 

 it is very great, rising to 4,000 parts per 

 million, and this fact must be kept in mind 

 in attempting to measure the changes in soil 

 reaction caused by the use of fertilizers. 



F. P. Veitch. 



CARBONATED MILK. 



In the course of an investigation relating 

 to the chemistry of kumiss made from cows' 

 milk, the question arose as to whether there 

 is any action of carbon dioxide on milk-casein. 

 No action appears to take place when carbon 

 dioxide is passed through milk simply at at- 

 mospheric pressure; but, since in kumiss the 

 gas is present under considerable pressure, it 

 was decided to approximate this condition by 

 treating fresh milk with carbon dioxide gas 

 under pressure. Without stating here the 

 detailed results of the work, it was noticed 

 that the milk thus treated did not sour or 

 curdle readily, keeping ten days to two weeks 

 at a temperature of 60° to Y0° F., when the 

 pressure used was sixty to seventy pounds. 

 Pasteurized milk keeps still longer. In addi- 



tion to prolonging its keeping power, milk, 

 when carbonated, makes a very palatable, re- 

 freshing beverage. Before the detailed results 

 are published, further work is being done, 

 carbonating the milk at higher pressure and 

 keeping it at different temperatures. 



L. L. Van Slyke, 

 a. w. bosworth. 

 New Yoek Agbicultubal Experiment 

 Station, Geneva, N. Y., 

 April 16, 1906. 



NOTES ON ORGANIC CHEMISTRY. 



PREPARATION OF PURE ETHYL ALCOHOL BY MEANS 

 OF METALLIC CALCIUM. 



Metallic calcium having now become a 

 regular article of commerce, several chemists 

 have investigated its properties, in order to 

 discover what advantages are likely to result 

 from its use in chemical reactions. For ex- 

 ample, in the chemical laboratory of the Johns 

 Hopkins University, experiments are in prog- 

 ress to determine how far it may be of service 

 in promoting the condensation of ketones with 

 esters (Claisen's reaction). 



L. W. Winkler* has examined its behavior 

 towards mixtures of alcohol and water. As is 

 well known, there is no special difficulty in re- 

 moving water from alcohol — say by means of 

 quick lime and copper sulphate — until it is 

 99.9 per cent, pure, but the elimination of the 

 last 0.1 per cent, of water has been attended, 

 hitherto, with considerable labor. By Winkler's 

 process commercial ' absolute ' alcohol, con- 

 taining usually several per cent, of water, is 

 boiled for a short time with calcium and then 

 distilled from it. About 20 grams of the 

 metal, in the form of turnings, to each liter 

 of alcohol should be used. The product con- 

 tains only 0.1 per cent, of water, which is re- 

 moved by another treatment with calcium, in 

 the proportion of 0.5 per cent, of the weight 

 of alcohol. A curious point about the be- 

 havior of calcium and alcohol is that, if the 

 latter contains less than 5 per cent, of water, 

 the metal is attacked the more vigorously the 

 less water is present, but, on the other hand, 

 ordinary alcohol, containing more than 5 per 



^Ber. d. CJiem. Oes., 38, 3,612. 



