1905.] PUBLIC DOCUMENT— Xo. an. 109 



counteract the action of the tree lime before subjecting the 

 samples to the usual treatment with neutral citrate of am- 

 monia for the dermination of the available phosphoric acid. 

 The attempt to imitate the phosphatic slag, by fusing 

 apatite with soda ash at 600° to 800° C, Avas mentioned in 

 our })revious annual report. Observations have been ex- 

 tended along this line during recent years by fusing natural 

 phosphates with carnallite and kieserite for ten to fifteen 

 minutes, at a temperatiu-e of 650° to 800° C. This treat- 

 ment gave a compound analyzing : — 



It was reported that the effect of this fertilizer on oats and 

 peas was somewhat superior to phosphatic slag, as regards 

 the yield of o'rain. 



Another substitute for slag phosphate is described by 

 Prof. P. Wagner : 100 parts of coarsely crushed phosphorite 

 is fused with 70 parts of acid sodium sulfate ; 20 parts of 

 calcium carbonate, 22 parts of sand and 6 to 7 parts of coal; 

 this gave a product testing 15.7 per cent, phosphoric acid, 

 practically all of Avhich was soluble in citric acid solution. 

 Pot experiments were conducted on oats, grown on loam 

 soil, by the aid of this mixture, alongside of similar experi- 

 ments conducted with a superphosphate testing 17.7 per 

 cent, water-soluble phosphoric acid and 18.9 per cent, total 

 phosphoric acid and phosphatic slag, testing 18 per cent, 

 citric acid soluble phosphoric and 19.9 per cent, total phos- 

 phoric acid. The fused mixture gave as quick-acting and 

 effective results as the superphosphate, and also gave results 

 superior to the basic slag phosphate. 



During the winter of 1902 Mr. H. D. Haskins of this 

 department made some interesting experiments in fusing 

 Canadian apatite Avith a mixture of sodium and potassium 

 carbonates. The apatite was a high-grade material, testing 



