FERtiiilZERg. 



837 



phopphate, the method of mannfaoture of wliich was invented by the Swedish 

 chemists Wibor<i;h and Pahnaer, forms a pure white light powder without crystal- 

 line structure. Chemical analysis showed its composition to be as follows: Hygro- 

 scopic moisture, water, fluorin, etc., loss on ignition, carbon dioxid, 12.15 per cent; 

 phosphoric acid, 35.73 per cent; lime, 48.83 per cent; soda, 1.57 per cent; insoluble 

 residue, 1.71 per cent. 



By treating 1 gm. of tlic pli(isi)lialt' with 200 cc. 2 per cent citrate solution at 

 17.5' C. for 30 minutes in a rotary aj)paratus and determining the phosphoric-acid 

 content of the clear filtrate, a citrate solubility of 90.96 per cent of the total phos- 

 phoric-acid content was found, thus showing a great similarity to bone meal. In a 

 sample of steamed 1)one meal treated by the same method of analysis 94.76 per cent 

 of the phosphoric acid was soluble in citrate solution. The chemical analysis of the 

 phosphate also shows it to stand near bone meal, as it is essentially a tricalcium 

 orthophosphate. 



The pot experiments were conducted with a poor sandy soil of the kind previously 

 used at this station in the experiments with Wiborgh phosphate (E. S. R., 10, p. 

 32), giving up on treatment with hot hydrochloric acid of 1.15 sp. gr. only 0.044 per 

 cent jihosphoric acid, 0.037 per cent potash, and 0.404 per cent lime. In addition 

 to small quantities of linely-powdered marble, sodium chlorid, sulphate of magnesia, 

 sulphate of potash (at the rate of 300 kg. potash per hectare), and nitrate of soda (at 

 the rate of 100 kg. nitrogen per hectare), phosphates were added in three series, in 

 the form of precipitated calcium phosphate, Thomas slag, and superphosphate, at 

 the rate of 100, 150, and 200 kg. of citrate-soluble phosphoric acid per hectare in 

 each ca.«e. The yields of oats obtained in these trials compared with those obtained 

 without application of phosphoric acid (this being equal 100) are shown below: 



Comparative yields of oats with different phosphates. 



In earlier comparative fertilizer experiments with bone meal and Thoma.s phos- 

 phate, conducted under similar conditions,' bone meal gave the following relative 

 yields, when applied at the rate of 100, 150, and 200 kg. per hectare (no phosphoric 

 acid = 100): 101, 142, and 172, and Thomas slag, 427, 500, and 542. The new pre- 

 cipitated phosphate is therefore more like bone meal in its action than Thomas slag, 

 and according to our present limited knowledge may he considered of approximately 

 the same value as bone meal. — f. w. woll. 



Comparative experiments with nitrogenous fertilizers, C. PKL.\UMEFt 

 ( Wchnbl. Landiv. Ver. Bayern, 1901, pji. 398, 434, 437, 489; ahs. in Cenlbl. Agr. Chem., 31 

 {1902), No. 1, pp. 3, 4). 



Refuse molasses solutions as a fertilizer, Bartos {Oesterr.-Vngar. Zlschr. 

 Zuckeriiiil. v. Linidir., 30 {1901), p. 754). 



Phosphate rock, E. W. Parker {Mineral Resources of the United States. Dept. 

 Interior, U. S. (>eol. Surrey, 1900, j>p. S03-S 14). —The production of i)hosi)hate in tlie 

 United States during 1900 was 1,491,216 long tons against 1,515,702 tons in 1899, a 



'K. Landt. Akad. Handl. Tidskr., 1892, p. 302. 



