202 



NATURE 



[April 15, 1920 



be rendered independent of imported nitrogenous 

 fertilisers, as is surely desirable — and recent con- 

 ditions have shown that it may at any time 

 become even absolutely necessary — and if this is 

 to be coupled with a continued large export trade 

 in nitrogen products, we must have a considerably 

 increased production of ammonia nitrogen. 



So far, practically all the by-product nitrogen 

 has come from the manufacture of coal-gas, pro- 

 ducer-gas, coke, and shale-oil ; two possible 

 sources have been praqtically untouched, viz. 

 peat and sewage, though from the latter, 

 owing to our position, perhaps little may be ex- 

 pected — certainly so unless some simple method 

 should be discovered for recovering the soluble 

 nitrogen from very dilute material. At the same 

 time, it may be pointed out that the estimated 

 annual amount of nitrogen in the sewage of the 

 United Kingdom is 234,900 metric tons, 86 per 

 cent, of which is in urine. 



Power cost is, of course, the great factor in 

 the question of by-product recovery versus syn- 

 thetic manufacture, and this is affected by coal 

 cost : the problem is fully discussed in the report. 

 But questions of the first importance to the by- 

 products industries, which must strive to increase 

 production, are such questions as the efficiency 

 of work on existing processes, the modification 

 and further development of such processes, and 

 the introduction of new methods. 



Reviewing the gas industry, it is seen that, 

 with existing methods, an increase in the amount 

 of sulphate of ammonia recovered should certainly 

 be expected. Many small gas-works run to waste 

 the ammonia liquor, chiefly owing to their isolated 

 position ; a proposal is made in the report to 

 work up liquors at small works in travelling 

 sulphate plants, but this has been attempted in 

 several instances and afterwards abandoned. 

 One would remark, however, that some small 

 works might well adopt the direct system of re- 

 covery, which has in some cases served very 

 well, and a local demand for the sulphate pro- 

 duced would obviate cost of transport. A general 

 consideration of the direct method of recovery 

 demands more attention than has been given to 

 it ; much has been done and published in recent 

 years by the Chief Alkali Inspector. Storage of 

 ammoniacal liquor still needs attention ; there are 

 in use inefficient methods of running ammoniacal 

 liquor into imperfectly covered wells and tanks : 



this point is strongly indicated in the report. In 

 dealing with concentrated ammonia liquor, the 

 losses are apt to be particularly heavy. It is con- 

 sidered that several thousand tons of sulphate 

 might be added yearly to the gas industry ammonia 

 recovery by attention to such matters as these. 

 Moreover, it will be necessary to produce a some- 

 what higher grade and at the same time a neutral 

 sulphate. But a question that demands perhaps 

 even more attention is the introduction of new 

 methods whereby the sulphur content of the gas 

 itself would be made available, and so transport 

 and use of sulphuric acid avoided. The Burk- 

 heiser and Feld processes still require to be 

 worked out satisfactorily, and quite recently 

 comes the proposal of Cobb to use sulphate of 

 zinc as a starting material. These methods 

 are perhaps all the more worthy of careful investi- 

 gation owing to modern developments in the 

 manufacture of coal-gas ; the increase in the 

 vertical retort method of carbonisation, coupled 

 with steaming, has given rise to increased quan- 

 tities of liquor of decreased strength. 



In the metallurgical coke industry many of the 

 bee-hive plants have disappeared in recent years, 

 and this has, of course, had its effect on the 

 ammonia production. There is now no longer any 

 question as to the relative merits of bee-hive and 

 by-product oven coke, and proper treatment might 

 lead to an increase of 10 per cent, or more on 

 the present total production of ammonia from all 

 sources. 



In the producer-gas industry, again, there is 

 scope for investigation ; scarcely sufficient stress 

 appears to be laid on producer-gas practice as 

 regards steaming and liming. Hydrated lime 

 certainly has a quite appreciable effect on 

 ammonia production, and it would seem, more- 

 over, to admit of greater latitude in the choice of 

 the coal used. 



It is unfortunate that peat has not received 

 more attention in this country ; apart from nitro- 

 genous by-products, some of the by-products from 

 peat gasification appear to have quite a special 

 value, judging from results obtained in Scotland 

 and Ireland. Moisture and transport are, how- 

 ever, difficulties, yet schemes for the utilisation 

 of peat on the spot might well be considered from 

 a power point of view, even though the addition 

 to the by-product nitrogen production would not 

 be by any means of the first order. 



A Survey of National Physique.^ 



ONE of the more valuable after-results of the 

 gi'eat wars in the last century was the 

 increased interest aroused in regard to national 

 physique, leading to various measures directed 

 towards its improvement. After the Napoleonic 

 wars there arose the great gymnastic clubs of 



' Ministry of National Service 1917-19. Report, vol. i., upon the 

 Physical Examinafon of Men of iMilitiiry Age by National Service Medical 

 Boards from Novem'^er i, iqiy-Ociober 31. 1918. Pp. iv-t-159+charts. 

 (London : H.M. S'ationery Office, 1920 ) t'rice 6^. net. 



NO. 2633, VOL. 105] 



Central Europe and Scandinavia, which laid the 

 foundations of physical education oni a wide scale. 

 The Civil War in America led to the first great 

 demographic survey, the data of which were ren- 

 dered public in the report of the Surgeon-General 

 of the Federal armies on the statistics of the 

 recruiting bureaux. The War of 1870 was followed 

 by surveys of the population in Germany, and on 

 a smaller scale in France, which to a large extent 



