322 



NATURE 



[May 12, 1921 



the former contain a large proportion of magnesic 

 chloride, whilst the latter are practically free from 

 this objectionable impurity. 



In addition to the Alsatian and German de- 

 posits, a number of other deposits are known. 

 There are deposits in Galicia, which have been 

 worked in a small way for some years, as also 

 at Erythrea, in Italy, and the existence of a 

 number of others that have not yet been worked 

 has been recorded. It appears that the recently 

 discovered deposits in Catalonia, Spain, are likely 

 to prove quite important. In several parts of the 

 world lakes rich in potash salts have been worked 

 — e.g. in Tunis, in Chile, and in the United 

 States. Those in the last-named country occur in 

 Central Nebraska, and produced salts carrying 

 40,000 tons of K2O in 1918, the producing capa- 

 city being estimated at 50,000 tons, or about one- 

 half of the total producing capacity of the entire 

 United States. 



In this country the only practically available 

 source of supply is the flue-dust from blast- 

 furnaces. It has long been known that this dust 

 contains > potash, but the amount was small, and, 

 worse still, very variable, depending largely upon 

 the working of the blast-furnace. As the result 

 of a number of experiments initiated by Mr. K. M. 

 Chance, of the British Potash Co., Ltd., it was 

 discovered that by adding a small proportion of 

 salt to the blast-furnace charge, practically all the 

 potash present could be volatilised as chloride 

 and recovered in the flue-dust. Messrs. Rossiter 

 and Dingley investigated for the above company 

 the percentages of potash in a large number of 

 iron-ores, and published their results in 

 November, 1919, in the Journal of the Society of 

 Chemical Industry. The ores richest in potash 

 are the bedded ironstones of Secondary age, such 

 as those of Northamptonshire, Cleveland, Lincoln- 

 shire and Oxfordshire, which showed respectively 

 0-42 per cent;, 0-36 per cent., 0-36 per cent, and 

 030 per cent, of potash. When salt is added to 

 the charge of a blast-furnace smelting these ores, 

 flue-dusts are obtained that contain about 30 or 

 35 per cent, of KoO as chloride or other water- 

 soluble salts. Such dust is, therefore, consider- 

 ably richer in potash than the ordinary manurial 

 salts hitherto supplied from Germany, and it 

 seems probable that it could be applied direct to 

 the land with very beneficial results, though not 

 much work has as yet been done in this direction. 



The experiment of adding salt to the blast- 

 furnace charge has as yet been tried in only a 

 few works, and the bulk of the dust thus produced 

 NO. 2689, VOL. 107] 



appears to have been worked up for potash salts 

 at the works of the British Potash Co., Ltd., at 

 Oldbury. In the paper already referred to, it is 

 calculated that if the salt process were adopted 

 in every blast-furnace in Britain, potash equivalent 

 to 50,000 tons of KgO could be recovered annually. 

 This figure is about double that of the British 

 consumption of potash for agricultural purposes 

 before the war, but falls far short of the amount 

 that we really require in this country, whilst it 

 need scarcely be said that nothing even remotely 

 approaching it has as yet been produced, nor does 

 there appear to be the slightest prospect of reach- 

 ing it for many years to come. 



In the meantime, British agriculture needs 

 potash and needs it most urgently. Agriculture 

 is the most vital of our industries, and when the 

 process of destroying our coal-mining industry, 

 and with it our manufacturing industries gene- 

 rally, now apparently in full swing, has been con- 

 summated, it will be the only means by which the 

 inhabitants of these islands can continue to exist. 

 It would appear, therefore, that the best policy in 

 our national interests is to help our French Allies 

 to develop as speedily as possible the potash re- 

 sources of their recovered province, and to obtain 

 from them the supplies of potash which our lands, 

 neglected in this respect during the war, so 

 sorely need. Of course, the potash-bearing 

 blast-furnace flue-dust would continue to be 

 worked up, as it is at present, for the manufacture 

 of high-grade salts of potash, and no doubt it 

 would be able to supply a certain proportion cf 

 the British consumption of such salts, and to this 

 extent decrease our imports. 



Human Palaeontology. 



Les Hommes Fossiles : Eldments de Paleontologie 

 Humaine. By Prof. Marcellin Boule. 



Pp. xi-l-491. (Paris: Masson et Cie, 1921.) 

 40 francs net. 



ON opening the covers of this magisterial work 

 by Prof. Marcellin Boule, one has the feel- 

 ing of having entered a court of justice where 

 a severe judge has conveyed to counsel and to 

 witnesses that his cases are to be tried according 

 to the strict law of evidence, and that he will 

 stand no nonsense. All the cases on which is 

 based our conception of the antiquity and origin 

 of man come up for review ; judgments are duly 

 given in such clear, unmistakable terms that they 

 carry with them an air of finality. For example, 

 there is the case for eoliths — whether they have 

 been fashioned by the hand of man or by Nature ; 



