Dr. A. Holmes — Non-German Sources of Potash. 347 



collection of sun-flower stalks from the Russian peasants, and no 

 doubt under settled conditions this source will again become 

 productive. Cream-of-tartar is a by-product of the wine industry, 

 and is exported in large quantities from France, Italy, and other 

 wine-producing countries. 



Reference to the chief animal source of potash has already been 

 made in connexion with saltpetre; wool, grease, and dried sweat 

 (suint) remain for brief consideration, for this material, the waste 

 product from processes of wool-scouring, contains the potash salts of 

 various fatty acids. In France and Belgium K 3 C0 3 has been 

 recovered from suint liquors for several years, and under war 

 conditions its extraction was commenced in Britain. Incidentally 

 the treatment of suint is to be advocated, if only to avoid the fouling 

 of rivers which attends the usual method of its disposal. 



Insoluble Potash Minerals. 



The chief silicate minerals rich in potash are felspars (orthoclase 

 and microcline), leucite, micas, and glauconite, while a mineral 

 which may conveniently be considered with these is alunite, a basic 

 sulphate of potassium and aluminium. 



Felspars. — Although numerous attempts have been made to devise 

 a commercially successful method of separating potash from felspar, 

 none has yet satisfactorily emerged from the experimental stage, 

 except possibly where the separation is introduced into, and made 

 part of, the process of manufacturing Portland cement (see below, 

 p. 348). In Britain 1 our potash -felspars are not well situated, and 

 the cost of quarrying and carriage forbids their utilization as a source 

 of potash, and is likely to do so unless the very bulky residue can 

 itself be employed in a profitable capacity. 



Leucite. — Leucite contains about 19*5 per cent of potash, and as it 

 is readily decomposed by acids, giving a solution of potassium and 

 aluminium salts, it certainly provides a more favourable material for 

 treatment than felspar. The leucitic lavas of the Italian volcanoes 

 contain between 8 per cent (leucite-tephrite) and 10 per cent of 

 K 3 (leucite-phonolite), and those of the Leucite Hills in Wyoming 3 

 average 10 per cent; consequently these rocks might be treated 

 directly, and they are undoubtedly a valuable potential asset to the 

 countries in which they occur. H. S. Washington 3 has recently 

 drawn attention to this comparatively neglected source of potash in 

 an elaborate review of the Italian lavas, in the course of which he 

 estimates the reserves of potash in the seven leucitic volcanoes, 

 extending from Vesuvius to Bolsena, at a minimum of 10,000 million 

 tons. The corresponding American resources are but a fiftieth of 

 this amount, and are, moreover, less favourably situated with respect 

 to industrial centres. Already, in both areas, the rocks have been 

 used directly as fertilizers, and the American Potash Company has 



1 Mem. Geol. Surv. , Spec. Reps, on Mineral Resources, vol. v (Potash-Felspar, 

 etc.), 1916; P. G. H. Boswell, Trans. Soc. Glass Technology, vol. ii, p. 35, 

 1918. 



2 R. C. Wells, U.S.G.S., Prof. Pap. 98 D, p. 37, 1916. 



3 Met. & Chem. Eng., vol. xviii, p. 65, 1918. 



