SOILS FERTILIZERS. 331 



oess of lime in the fusing mixture which formed an unfused residue resulted in 

 the formation of insoluble calcium phosphates, and the phosphoric acid content 

 soluble in Petermann's reagent was decreased. The addition of sand to the 

 fusing mixture had a favorable effect, attributed to the neutralization of in- 

 jurious excesses of lime and to the possible formation of phosphate of silicon. 

 The mixture of phosphorite, sodium sulphate, and carbon when fused for 1,5 

 hours showed 21.63 per cent of its phosphoric acid to be soluble in Petermann's 

 reagent, as against 60.68 per cent of that in Wolter's phosphate. After 3- 

 hours' fusion 57.33 per cent of the phosphoric acid of the mixture was avail- 

 able, as against 69.93 per cent of that of Wolter's phosphate. 



The influence of temperature in the extraction of Thomas slag with citric 

 add, W. HoLUE (Chem. Ztg., 38 {1914), No. 128-129, p. 1155; abs. in Chem. 

 Zentbl., 1914, II, No. 25, p. 1409). — In three series of experiments using 2 per 

 cent citric acid for 15 minutes at average temperatures of 17.5, 24.5, and 26.5° 

 C. the average difference in phosphoric acid extracted from Thomas slag was 

 0.034 per cent per degree of difference in temperature. 



The assimilation of reverted phosphoric acid by plants, V. P. Kochetkov 

 {Iz Rezul't. Vcget. Opytov Lab. Rabat, 9 (1913), pp. 187-147, figs. 5).— This is 

 a report of the third year's sand-culture experiments with different phosphates 

 (E. S. R., 30, p. 428). The phosphoric-acid fertilizers tested were (1) the 

 residue obtained after evaporation to dryness of a water solution of a phos- 

 phate treated with sulphurous acid, (2) the lime precipitate of a solution of 

 Viatka pho.sphate in sulphurous acid, (3) enriched superphosphate obtained by 

 treatment of precipitated phosphate with sulphuric acid, and (4) nitro- 

 superphosphates obtained fi-om the waste liquor of trinitro-toluene works. 



As in the previous experiments, excellent results were obtained with the 

 superphosphates obtained from the Viatka phosphate and with the nitrosuper- 

 phosphates. The second phosphate had a good effect, but the third had a de- 

 pressing effect on the crop, due, it is thought, to the presence of sulphites. 



The action of sulphur on plant production, T. Pfetffer and W. Simmeb- 

 MACHER Fiihling's Landw. Ztg., 64 (1915), No. 9-10, pp. 243-255, fig. 1).— Pre- 

 vious experiments by Pfeiffer and Blanck (E. S. R., 31, p. 220) and work by a 

 number of others bearing on the subject are briefly reviewed and field experi- 

 ments with beets are reported. In the latter practically the same results were 

 obtained as with oats in the previous experiments. 



These results are taken to indicate that sulphur fertilization is wholly in- 

 effective on the soil used in the experiments. It is concluded that in the light 

 of present knowledge a recommendation for the general use of sulphur as a 

 fertilizer in agricultural practice is not justified. 



The fertilizing' action of sulphur on vines, D. Zolla (Rev. 06n. Sci., 26 

 (1915), No. 4, pp. 120, 121). — Experiments by Chauzit are reported, the results 

 of which showed that sulphur has a more marked effect when used as a fer- 

 tilizer when the soil is well stocked with organic matter. The effect of the 

 sulphur decreased as the content of organic matter decreased. The action of 

 the sulphur is increased when it is mixed with organic matter and when it is 

 used in large amounts. 



Fertilizer experiments with the sulphate and carbonate of manganese, 

 Or. D'Ippolito (Stas. Sper. Agr. Ital., 47 (1914), No. 8, pp. 621-626; abs. in 

 Chem. Zentbl., 1915, I, No. 8, p. 592). — In plat experiments with medicinal 

 herbs and cereals on a natural clay soil to test the fertilizing value of manga- 

 nese carbonate and sulphate, a marked inci'ease in crop yield was obtained with 

 both compounds. Both are concluded to be valuable catalytic agents in con- 

 nection with the fertilization of crops. 



Radium fertilizer, R. R. Ramsey (Science, n. ser., 42 (1915), No. 1076, p. 

 219). — On the basis of an estimate that the upper 5-in. layer of an acre of soil 



