424 EXPERIMENT STATION RECORD. IVol. 38 



It was found that In the case of the Inorganic acids the solubility of the 

 phosphoric anhydrid in superphosphate was comparable with that obtained 

 with the mineral phosphates, after making allowances for such factors as fine- 

 ness, friability, and proportion of lime. In the case of the organic acids, 

 mineral phosphates behaved in the same way as wlien treated with inorganic 

 acids, except that there was a slighter dissociation and that the influence of 

 other constituents was more pronounced. Superphosphates, however, behaved 

 in the same way as mineral phosphates toward oxalic acid, but yielded a 

 high proportion of phosphoric anhydrid to the other solutions. For example, 

 the following amounts of the total phosphoric anhydrid were extracted : With 

 formic acid 73.28, acetic acid 02.61, oxalic acid 24.44, tartaric acid 66.43, and 

 citric acid 77.87 per cent. 



" The formation of complex citrophosphates in combination with aluminum 

 and ferric iron has been shown [E. S. R., 36, p. 727] to be the cause of the high 

 citric solubility of phosphoric acid, and it would seem that similar complex 

 compounds are formed with organic acids containing atoms of hydrogen not in 

 combination in carboxyl or hydroxyl groups. The solubility of the phosphoric 

 anhydrid in superphosphates is somewhat less than that of mineral phosphates 

 in dilute mineral acids, but the solubility of the phosphoric anhydrid is almost 

 equal in both cases in organic acids which have the property of forming com- 

 pounds with phosphoric acid, aluminum, and ferric iron." 



Fertilizer trials with tetraphosphate in Piedmont rice fields, Italy, Mak- 

 CARELLi and NovELJLi (Gior. Risicolt., 6 (191G), No. 21, pp. 321-327; abs. in 

 Internat. Inst. Ayr. [Ilotne], Internat. Rev. Sci. and Fract. Ayr., 8 (1917), No. 

 2, pp. 230, 231; Jour. Soc. Chetn. Indus., 36 {1917), No. 15, p. 897).— Experi- 

 ments were made in an extremely acid soil, very poor in lime, growing rice. 

 The field was in a fertile condition at the commencement of the experiments, 

 having received a dressing of mineral superphosphate and barnyard manure dur- 

 ing the previous winter. Three equal areas of the field were sown with paddy 

 rice and manured, respectively, with 500 kg. per hectare (445 lbs. per acre) 

 of tetraphosphate containing 2 per cent of citrate soluble, 7.8 per cent of citric 

 acid soluble, and 2S.3 per cent total phosphoric acid, the same amount of ground 

 phosphorite, and 930 kg. of superphosphate. The amount of marketable grain 

 obtained from the tetraphosphate plat was 6,330 kg., from the ground phos- 

 phorite plat from 5,730 to 5,906 kg., and from the superphosphate plat 5,690 kg. 



What we are doing toward remedying the potash shortage, R. K. Meade 

 {CommGrcial Fcrt., 15 {1917), No. 3, pp. 1,0, U, 46, 50).— This is a brief review 

 of the details of the different new potash industries of the United States. It is 

 believed " that the largest future source of cheap potash available in the 

 country is in the iron industry and cement industry, which could be made to 

 produce almost all of the potash formerly imported from Germany. Other 

 promising sources of small amounts are from the evaporation of brines and 

 from beet-sugar waste. There is always the possibility, too, that some of the 

 processes now proposed for the manufacture of potash direct from greensand 

 or feldspar will prove commercially successful." 



A new source of potash, H. T. Cranfield (Jour. Bd. Agr. [London^, 24 

 (1917), No. 5, pp. 526-530; abs. in Nature [London], 100 (1917), No. 2501, 

 p. 92). — The author is of the opinion that the flue dust of blast furnaces is the 

 most important source of potash yet discovered in Great Britain. Analyses of 

 flue dusts are given in the table following. 



