SOILS — FERTILIZERS. 221 



The phosphates were ground to a size of from to 0.5 mm. in diameter and were 

 sifted into two fractions below and above 0.08 mm. 



The greatest difference in phosphoric-acid content of the two fractions was 

 obtained with the first phosphate series, containing an average of 16 per cent 

 phosphoric acid, where the fine-grained fraction contained 24 per cent phosphoric 

 acid and the coarse-grained fraction 13 per cent. Anotlier series showed only a 

 small difference, and three series no difference. The sixth sample, containing 

 from 26 to 27 per cent phosphate, showed results opposite to those obtained with 

 the first sample, the coarse-grained fraction being the richer in phosphoric acid. 

 The theory underlying this phenomenon is explained. After a preliminary roast- 

 ing of the first series of phosphates it was found that the fine fraction contained 

 the more phosphoric acid. 



The effects of caustic lime and of chalk on soil fertility, H. B. Hutchinson 

 and K. MacLennan {Rpt. Brit. Assoc. Adv. Sci., 1914, pi). 668, 66'J).— This ar- 

 ticle briefly summarizes the results of investigations discussed in previous re- 

 ports (E. S. R., 33, p. 622). 



Lime and the American vine, G. de Angelis D'Ossat (Sta:;. 8 per. Agr. Ital., 

 47 il'JlJi), No. 8, pp. 603-620, figs. 2; ahs. in CJiem. Zentbl, 1915, I, No. 8, p. 392; 

 Chem. Ahs., 9 (1915), No. 12, pp. 1653, i65/f).— References to the work of others 

 bearing on the subject are cited and culture experiments with different vine types 

 are reported, from the results of which it is concluded that chlorosis is not so 

 dependent on the absolute amount of calcium oxid in the soil as on its relative 

 solubility. An apparatus for determining its solubility is described. The crystal 

 system to which calcium oxid compounds belong also influences the solubility, 

 owing to the surfaces presented to attack, calcite dissolving much more readily 

 than aragonite. Other soil constituents, especially clay and humus, influence the 

 solubility of the lime by their effect on the physical and chemical structure of the 

 soil. 



The gypsum industry in 1914, G. F. Loughlin (U. S. Geol. Survey, Mineral 

 Resources of the United States Calendar Year 1914, pt, 2, pp. 261-270, fig. 1). — 

 This report deals with the production of gjT)Sum in this and other countries and 

 with imports and trade conditions and reviews the history of gypsum production 

 in this country since 1880. The number of short tons of raw gypsum mined in 

 1914 was 2,476,465, or a decrease of 123,043 tons from the quantity mined in 1913. 

 The quantity of raw gypsum ground and sold for land plaster in 1914 was 52,945 

 short tons, or a decrease in quantity of 1,870 tons from 1913. 



Relation of sulphur compounds to plant nutrition, E. B. Hakt and W. E. 

 ToTTiNGHAM ({7. S. Dcpt. Agr., Jour. Agr. Research, 5 (1915), No. 6, pp. 233-250. 

 pis. 3). — Data are presented from greenhouse studies at the Wisconsin Experi- 

 ment Station with one type of soil (Miami silt loam) indicating that certain 

 plants are measurably increased in their growth by addition of sulphates. Pre- 

 vious experiments have shown that sulphates have little effect as compared with 

 soluble phosphates on the soil flora, and this limits the number of crops for which 

 sulphates may be expected to prove an effective fertilizer. Leguminosse and 

 Cruciferse plants made the most marked response to sulphates. In general cal- 

 cium sulphate was more effective than sodium sulphate. The influence of the 

 sulphates was most marked in the case of root development, the sulphates being 

 particularly effective in this respect with red clover and rape. The well-known 

 benefit of gypsum to red clover is correlated with this special effect of sulphates 

 on root development, as well as the high percentage of protein in clover, making 

 a special demand for sulphur. In these experiments elemental sulphur was gen- 

 erally harmful, this being attributed to incomplete oxidation of the sulphur or 

 to acidity resulting from the formation of sulphuric acid. 



A bibliography of 16 references to literature on the subject is given. 

 22434°— No. 3—16 3 



