19161 SOILS — FERTTLIZEES. 521 



deficient in phosphoric acid but rich in humus, are reported, in which 11 

 different slags were used as fertilizer at the rates of 50 and 200 lbs. of phos- 

 phoric acid per acre. The results of analyses of the slags are also reported, 

 and a correlation of these with the citric solubility of the slags and with the 

 results of the plat experiments indicated that phosphate is the most important 

 constituent of slag, while magnesium, manganese, and iron stand second in 

 importance and are of about equal weight. "There seems much reason for 

 supposing that a balance of the secondary constituents is needed. . . . 

 Medium proportions of magnesia, manganese, and iron are all useful, but 

 extra large proportions harmful." 



Experiments on the solubility of the phosphoric acid in Thomas meal in 

 water saturated with carbon dioxid, J. G. Maschhaupt {Verslag. Landbomvk. 

 Onderzoek. Rijkslandbouioproefstat. [NetJierlands], No. 17 (1915), pp. 97-141, 

 figs. 5; abs. in Chem. Zentbl., 1915, II, No. 10, p. 552). — Experiments with 59 

 samples of Thomas meal are reported, the ratios of Thomas meal to water 

 used being 1 : 4,000, 1 : 2,000, 1 : 1,000, 1 : 500, 1 : 250, 1 : 125, 1 : 100, and 1 : 50. 



It was found that the amount of phosphoric acid dissolved from Thomas 

 meal by contact with water saturated with carbon dioxid depended in large 

 measure on the ratio of Thomas meal to water. The more narrow this rela- 

 tion was the stronger was the influence of the free calcium oxid and calcium 

 silicate in the Thomas meal on the solubility of the phosphoric acid. Thomas 

 slag meals of different citrate solubility showed also different solubilities of 

 their phosphoric acid in water saturated with carbon dioxid. Samples of high 

 citrate solubility yielded the greater amounts of phosphoric acid by the carbon 

 dioxid water method. After a certain number of extractions the solubility of 

 the phosphoric acid in the different Thomas meals became uniform. 



The amount of calcium not combined with phosphoric acid appeared to be 

 about the same in the different samples tested. The content of the free lime 

 was greater the smaller the citrate solubility, while the content of calcium 

 silicate was greater with greater citrate solubility. It is thought that the 

 varying citrate solubility is only in small part due to the variable content of 

 free calcium. When the free calcium was separated out the solubility of the 

 phosphoric acid by extraction with 2 per cent citric acid and with water 

 saturated with carbon dioxid was increased but the differences in solubility 

 still existed. These differences are attributed to the calcium phosphate itself, 

 which it is thought may exist in a double compound of calcium phosphate and 

 calcium silicate. Further experiments showed that in spite of the smaller 

 differences in citrate solubility important differences in solubility as indicated 

 by the first extraction with water saturated with carbon dioxid could enter. 



The results are taken to indicate that the relations found between citrate 

 solubility and solubility in carbon dioxid water do not yet show that the citrate 

 solubility can be used to indicate the value of Thomas meal. 



Results of g'eological investigation of phosphorite beds in Russia, 1913, 

 jA - Samoilov (J. Samoiloff) {Otchet Geol. Izsliedov. Fosfor. Zaleshei, 6 

 (1914), PP- 1-29; abs. in Internal. Inst. Agr. \_Rome'\, Mo. Bui. Agr. Intel, and 

 Plant Diseases, 6 (1915), No. 12, pp. 1594, 1595). — Investigations of the phos- 

 phorite beds of east and northeast European Russia, central European Russia, 

 and central Asia are reported. 



It was found that in the eight Provinces and regions the deposits cover an 

 area of 1,840 square miles. "Adding this area to that discovered in the years 

 1908-1912, the total area becomes 4,510 square miles, containing not less than 

 3,300,000,000 tons of phosphorites, reckoning the yield at about 5 cwt. per 

 square yard. These phosphorites may be divided into three groups according 



