628 EXPERIMENT STATION RECOED. 



Alimite as a source of potash, W. H. Waggaman (U. S. Dept. Agr., Bur. 

 Soils Circ. 70, pp. 4, figs. 2; Orig. Comniun. 8. Internat. Cong. Appl. Chetn. 

 [Washington and Neiv York], 15 {1912), Sect. VII, pp. S75-379, figs. 2).— This 

 circular describes the method and apparatus used to determine the temperature 

 at which complete decomposition of alunite takes place. It was found that at 

 a temperature of 700° C. alunite is completely decomposed, yielding a residue 

 of potassium sulphate and alumina. The alunite used in these experiments con- 

 tained 20.88 per cent of sulphur trioxid over and above that required to combine 

 with the potash present. Only 23.05 per cent, however, was recovered on 

 ignition, indicating a considerable loss as sulphur dioxid at the high temperature 

 of ignition used. The ignited residue contained 15.95 per cent of potash and 

 35.37 per cent of sulphuric acid (SOs). It is estimated that a ton (2,000 lbs.) 

 of pure alunite will yield 220 lbs. of potash, 1,090 lbs. of sulphuric acid, and 740 

 lbs. of aluminum, worth in the aggregate $13.88. 



In view of the diflSculty and expense of leaching potassium sulphate from the 

 ignited material, it is thought to be " more practical to use the ignited alunite 

 (free from soluble aluminum compounds) directly as a fertilizer either alone or 

 in mixed goods, since the expense of separating the soluble salts from the 

 alumina would probablj' more than counterbalance the value of the alumina 

 obtained. The percentage of potash in the ignited residue is considerably 

 greater than in kaiuit, our chief source of soluble potash." 



The extraction of potash from silicate rocks, W. H. Ross ( U. S. Dept. Agr., 

 Bur. Soils Circ. 71, pp. 10; Amer. Pert., 37 {1912), No. -'/, pp. U-'t9).— This 

 article describes and discusses the relative efficiency of various processes which 

 have been proposed for this purpose. It is stated that " on account of its sim- 

 plicity the method of decomposing feldspar by heating with calcium carbonate 

 and with calcium chlorid (or sodium chlorid) could undoubtedly be carried out 

 on a large scale without involving any serious mechanical difficulty, and the 

 method would thus be a practical one providing the value of the products 

 obtained would compensate for the expense involved," but the author is of the 

 opinion " that any method to be economical must produce at the same time other 

 products of value in addition to the potassium." 



Action of magnesium [and manganese] fertilizers and of boric acid, 

 P. Andouard {Engrais, 27 {1912), No. 2.9, pp. 796-799). — Experiments on a 

 variety of crops with a basic magnesium fertilizer with manganese (manganese 

 carbonate) and with boric acid gave as a rule inconclusive results. The only 

 fact which appeared to be definitely determined was that such fertilizers should 

 not be applied broadcast, but should be thoroughly mixed with the soil. 



Studies on catalytic fertilizers, E. Bouli^nger {Ann. Sci. Agron., J^. ser., 1 

 {1912), I, No. 3, pp. 161-180; Ann. Inst. Pasteur, 26 {1912), No. 6, pp. 456-^66: 

 abs. in Internat. Inst. Agr. [Rome], Bui. Bur. Agr. Intel, and Plant Diseases, 3 

 {1912), No. 9, pp. 195'), 1956). — In pot experiments with manganese chlorid. 

 alone and combined with other fertilizing materials, it was found that the use 

 of the manganese fertilizer resulted in a marked increase in the yield of potatoes, 

 but was practically without effect on barley. In similar experiments with 

 so-called manganose and lime manganate, it was found that the manganese 

 fertilizers increased the yield of oats, peas, and clover to a marked extent, par- 

 ticularly in the presence of potash salts and of a complete fertilizer containing 

 potash. 



Experiments are also reported in which manganese sulphate was compared 

 with aluminum sulphate, sodium silicate, ferrous sulphate, uranium sulphate, 

 and flowers of sulphur on a variety of vegetables. The effect of these substances 

 was variable, but in the majority of cases the yield was increased. The action 

 of flowers of sulphur was especially favorable. 



