1917] SOILS FEETILIZEES. 626 



reported. The amounts of potash in the dry plant were found to be as follows : 

 Sage brush 0.43 per cent, white sage 1.64, rabbit brush 0.75, Brigham tea 0.35, 

 and gi'easewood 0.96. 



Potash as a by-product from the blast furnace, R. J. Wysob {Bui. Amer. 

 Inst. Mining Engin., No. 121 (1911), pp. 1-32, figs. 20). — Data showing the 

 amount of alkalis, especially potash, occurring in the raw materials and in the 

 slag, cinder, dust, fumes, etc., of the blast furnaces of a large steel works are 

 reported and discussed with reference to the feasibility of recovering the potash 

 for sale. 



It is stated that with the gas-cleaning methods now used in the blast furnaces 

 there is a loss in the primary washers alone of over one-half of the total potash 

 charged, or from 9 to 12 lbs. per ton of pig iron produced. The amount re- 

 covered by these methods is less than 2 per cent of the total. About two-thirds 

 of the total potash charged is now lost in the wash water and stack gases, or 

 about 15 lbs. per ton of pig iron produced. Experiments with an electric dust 

 precipitator showed that practically all the dust and fume entering the treater 

 can be successfully precipitated by this means. The precipitated dust was 

 found to contain about 10 per cent of potash. It is suggested that while weak 

 acid treatment may be effective in making the potash of the flue dust soluble it is 

 not likely to be practicable, but that the soluble alkali salts can be recovered in 

 tolerably pure form by leaching and evaporation. 



The author is of the opinion " that in the future dry cleaning will be adopted 

 in many blast furnace plants, and that many thousands of tons of potash 

 hitherto wasted will be reclaimed." 



A bibliography of the more important articles bearing on the subject is 

 appended. 



Potash becom^es a valuable cement mill by-product, A. C. Hewitt {Engin. 

 News, 76 {1916), No. 26, pp. 1222-1226, figs. 5).— This is a description of a dust 

 precipitation plant of a cement mill at Hagerstown, Md., which not only reduces 

 the dust nuisance, but is said to be profitable for its production of potash. At 

 the present time, with two kilns 7 by 100 ft. and three kilns 8 by 125 ft., the 

 production of potash dust is said to average from 20 to 25 tons per 24 hours, 

 containing approximately 10 to 20 per cent of potassium sulphate. 



The effect of additions on the availability of soil potash, and the prepara- 

 tion of sugar humus, G. S. Praps {Texas Sta. Bui. 190 {1916), pp. 30). — Four 

 series of experiments are reported on the effect of additions of calcium car- 

 bonate, sawdust, sugar humus, corncobs, calcium sulphate, sodium sulphate, 

 sheep manure, and magnesium carbonate on the quantity of potash taken up 

 by crops of corn, cotton, sorghum, and oats from eleven soils, including Norfolk 

 sand, bottom land soil, sand, Norfolk fine sand subsoil, brown mesquite soil, 

 white sand, very poor upland soil, moderate upland soil, poor upland subsoil, 

 poor upland soil, and Norfolk white sandy loam subsoil. 



It was found that gains of potash due to the addition of calcium carbonate 

 or organic matter were comparatively small. The active potash of the soil 

 needed no addition of calcium carbonate, as it was already highly available. 

 Sodium sulphate and gypsum were often injurious. Plants were found to take 

 up an excess of potash over their actual needs. The percentage of potash in 

 the plants decreased as the amount of active potash in the soil decreased. 

 Additions of calcium carbonate did not increase the quantity of active potash 

 remaining in the soil at the end of the experiments. 



" The quantity of active potash lost is from 60 to 90 per cent of that taken 

 up by the crop, until the active potash is reduced so that the potash removed 

 actually comes from insoluble potash compounds and not from the active potash. 

 Active potash may be readily and rapidly removed by crops dowTi to the quan- 



