Dr. A. Holmes — Non-German Sources of Potash. 251 



II. — Non-German Sources of Potash. 



By Arthur Holmes, D.Sc, A.R.C.S., F.G.S. 



Introduction — Natural History of Potash — Saline Deposits — Alsatian Deposits 

 — Spanish Deposits — Abyssinian Deposits — Natural Brines — Searles Lake — 

 Nebraska and Utah — Tunis — Saltpetre — Kelp — Other Organic Sources — 

 Insoluble Potash Minerals — Felspars — Leucite — Glauconite — Alunite — Dust 

 from Cement Kilns — Blast Furnace Flue-dust. 



IT is scarcely necessary in this Magazine to insist upon the vital 

 importance of potash, or upon the reasons which led to the 

 former economic dependence of our own and many other countries on 

 German resources. The shortage of potash, which arose as a direct 

 consequence of the outbreak of war, became more and more 

 accentuated until the latter part of 1917, when production from 

 various revived and newly discovered sources began appreciably to 

 relieve the then seriously acute position. In 1913, the last complete 

 year of the older conditions, over £900,000 worth of potassium salts 

 were imported from Germany by Great Britain, against imports of 

 only half that value — much of which was cream-of-tartar, a by- 

 product of the wine industry — from all other countries. It is now 

 safe to say that the German monopoly is completely broken, partly 

 because of the return of Alsace to France, and partly because of the 

 discovery of new deposits, and the successful development, under the 

 stimulus of war conditions, of new methods of potash recovery from 

 sources formerly unremunerative or unsuspected. The purpose of 

 this article is to pass briefly in review the chief sources from which 

 potash is, or may be, profitably extracted, other than those of the 

 famous German deposits, which already have a voluminous and 

 familiar, or at least readily accessible, literature. 



The natural history of potash is very different from that of soda. 

 In average igneous rock the percentages of these two constituents 

 are practically equal, while in average sedimentary (exogenetic) 

 rocks potash is two and a half times as abundant as soda. Comple- 

 mentary to this selective retention, the potash of river waters 

 amounts to no more than a quarterof the soda, and in sea water the 

 proportion is still further reduced to a thirtieth. The following 

 figures, based on denudational statistics, bring out clearly the 

 difference of behaviour between the two elements. 



Potassium. Sodium. 

 (Figures represent millions of millions of tons.) 

 In ocean water ..... 450 12,600 



In sedimentary rocks .... 18,300 7,400 



18,750 20,000 

 In parent igneous rocks from which the 



sediments were derived . . . 19»700 20,000 



Unaccounted for .... 950 — 



In round figures the circulation of sodium is completely accounted 

 for, whereas a large balance of potassium, twice the quantity 

 dissolved in the oceans, remains over. This amount, or something 



