428 EXPERIMENT STATION RECORD. [Vol. 35 



action to sodium nitrate, although the latter is deemed generally preferable 

 as it is more easily stored and ;ised. 



The industry and commerce of nitrogenous substances, A. Bektrand {Asoc. 

 Sal. Propaganda BoJ. 8 (1915), Sup., pp. XV +155). — This report deals with 

 the sodium nitrate, ammonium sulphate, synthetic nitric acid, cyanamid, syn- 

 thetic ammonia, and aluminum nitrid industries, with the different processes 

 of manufacture involved in these industries, and with their relative commercial 

 standing. 



Experiments with phosphatic manures on green crops {Indian Tea Assoc, 

 Sci. Dept. Quart. Jour., No. 4 (1915), pp. 94-99). — Plat experiments with a 

 number of green crops, including white and brown cowpeas, on an acid soil 

 deficient in phosphoric acid, to determine the relative fertilizing value of a so- 

 called basic phosphate, degelatinized bones, superphosphate, and basic slag 

 showed that in their order the phosphorus fertilizers produced increases in 

 crop yield of 38, 164, 273, and 273 per cent. The basic phosphate was very 

 slow in action and is considered unsuitable for growing green crops on this soil. 

 The bone fertilizer gave rapid results, but was expensive, and its immediate 

 effect for the same price did not compare well with that of superpliosphate and 

 basic slag. In the absence of phosphoric acid no increase in crop was obtained 

 from the use of nitrogenous and potassic manures. 



A table showing the relative costs of the fertilizers for equal efficiencies is 

 also included. 



The solubility of different phosphates and their utilization by oats and 

 buckwheat, T. Pfeiffer, W. Simmermacher, and \\\ Rathmann (Landw. Vers. 

 Stat., 87 {1915), No. 2-3, pp. i9i-2i.^).— Pot-culture experiments with oats and 

 buckwheat and laboratory experiments with dicalcium and tricalcium phos- 

 piates and a coral rock pliosphate are reported, the purpose of which was to 

 determine the availability of the phosphoric acid of the phosphates to the crops 

 and the relation of its availability to its solubility in water saturated with 

 carbon dioxid. The dicalcium phosphate contained 50.65 per cent phosphoric 

 acid, the tricalcium phosphate 40.75 per cent, and the coral phosphate 39.82 per 

 cent. The last-named phosphate contained 10.78 per cent phosphoric acid 

 soluble in 2 per cent citric acid. 



It was found that the solubility of the phosphates as indicated by water 

 saturated with carbon dioxid did not always correspond with the availability 

 of the phosphoric acid as indicated by the cropping experiments. The buck- 

 wheat was better able to assimilate phosphoric acid from difficultly soluble 

 phosphates than was oats, this being attributed to the content of organic acids 

 in the root sap. 



Experiments on the action of the phosphoric acid in different Thomas 

 meals, Tacke, Gerlach, Schneidewind, Haselhoff, and Eberhart {Landw. 

 Vers. Stat., 87 {1915), No. 2-S, pp. 89-95, pis. 6).— Reports from five German 

 experiment stations of cropping experiments with 19 different types of Thomas 

 meal are reported, the purpose of which was to determine the relation between 

 the availability of the phosphoric acid in the different meals as indicated by 

 cropping experiments and the availability as determined by the 2 per cent 

 citric-acid method. It is concluded that there is no ground for rejecting the 

 method employing ammonium citrate solution containing 1.4 per cent free 

 citric acid for determining the availability of the phosphoric acid of Thomas 

 meal. 



Phosphates and phosphatic marls {Fla. Quart. Rul. Dept. Agr., 26 {1916), 

 No. 1, pp. 152-159).— Thin section of the report contains the results of analyses 

 of 31 samples of Florida phosphates and phosphatic marls. 



