1917] SOILS FEETILIZEBS. 817 



" The quantity mined in 1916 was 2,169,149 tons. Compared with the quantity 

 mined in 1915, which was 1,935,341 tons, this was an increase of 12 per cent, as 

 against a decrease of about 27 per cent in 1915 from 1914. In Florida the in- 

 crease was about 17 per cent, 24 companies operating in 1916 instead of 17, as in 

 1915. In South Carolina there was a decrease of 46 per cent and in Tennessee 

 an increase of 5 per cent. In Kentucky 1 producer reported rock mined. The 

 production in the Western States decreased 55 per cent. . . . 



" The western phosphate field includes about 2,500,000 acres, in which there 

 are about 5,750,000,000 tons of high-grade rock within minable depth (5,000 ft.) 

 of the surface, and in addition several billion tons of rock carrying from 15 to 

 40 per cent of tricalcium phosphate. Throughout most of the western field there 

 is a main bed from 3 to 6 ft. thick which runs over 65 per cent in tricalcium 

 phosphate. The workable deposits occur chiefly in public lands of the United 

 States. The character and mode of occurrence of the rock are such that for 

 the most part it must be mined by underground methods rather than by open 

 pits. The rock can be ground and treated with acid, however, without the pre- 

 liminary washing and drying which increase the cost of production of eastern 

 phosphates." 



Data on foreign sources of phosphoric acid are also given. 



Potash in agriculture. — III, Fiirther researches, B. C. Aston (Jour. Agr. 

 [New Zeal.], U {1911), No. 6, pp. U0-U7).—ln a further discussion of the 

 potash situation in New Zealand (E. S. R., 37, p. 218), it is pointed out that flax 

 waste, wood ashes from sawmills, hedge clippings, weeds, and liquid stock 

 excreta are some of the more important sources of potash in New Zealand which 

 are now disregarded or wasted. It is also thought that bracken as a source of 

 potash is worthy of investigation, as studies have sliown that New Zealand 

 bracken in the young stages contains as much potash as Scottish bracken and 

 gives a higher yield per acre. 



The recovery of potash from beet sugarhouse waste liquors, H. E. Zit- 

 KowsKi {Sugar [Chicago], 19 {1917), No. 7, pp. 256-258; Metallurg. and Chem. 

 Engin., 17 {1917), No. 1, pp. 17-19).— It is pointed out in this article that tech- 

 nically the recovery of the potash from beet sugarhouoe waste liquors is a com- 

 paratively simple and perfectly feasible problem. " It is simply one of evaporat- 

 ing the dilute liquors as economically as practical, charring the residue to pro- 

 duce the crude ash, and leaching and recrystallizing if this is desired. The 

 quantities of water to be evaporated, however, are large, the necessary equip- 

 ment costly, and commercially such a procedure has possibilities only during 

 war prices." 



Concentrated potash a by-product of cement mill {Engin. News-Rec, 78 

 {1917), No. IS, pp. 630-632, figs. 5).— Experience at a cement plant at River- 

 side, Cal., indicates that the possibilities of recovery of potash as a by-product 

 in Portland cement manufacture are that 90 per cent of the potash contained in 

 the raw mix can be volatilized, 10 per cent remaining in the clinker and 80 per 

 cent being caught by the dust collector. Including filter losses, it is considered 

 conservative to expect the recovery in the form of concentrated salt of 66f per 

 cent of the potash originally contained in the raw cement mix. A 100-ft. rotary 

 kiln, it is stated, may produce from 4 to 7 tons of dust daily, the average potash 

 content of which may range between 4 and 10 per cent. 



With reference to the mechanical features of the process, the dust is drawn 

 from bins under the electrical treatment into tanks, where it is put into solution 

 by agitation in water of not less than 85° C, at a concentration of not over 5 

 per cent K2O. The temperature soon rises to the boiling point, due to the hydra- 

 tion of the lime, and the potash goes rapidly into solution, the whole operation 



