MA3f;i.S-i9i^9] 



NATURE 



215 



effort of the army of chemists and engineers enlisted 

 under the command of Lord Mouhon. The necessity 

 for utiUsing all the chemical resources of the country 

 to the utmost led, in direct relationship with the 

 census of raw materials previously mentioned, to the 

 attempt to extract the last possible fraction of 

 efficiency in each component process. The huge pro- 

 duction just indicated made it very profitable to carry 

 out a vast amount of careful scientific investigation 

 of details of manufacture ; so many fellows of this 

 society devoted their best efforts to this work that 

 it would be invidious to mention names. Our col- 

 leagues have had ample opportunity to realise that 

 the romance of war is now to be found in the labora- 

 torv, the workshop, and the factory quite as much as 

 on the battlefield. 



An instructive example of the operations of the 

 struggle for economy in the production of a given 

 effect is found in the rivalry which arose between 

 picric acid and ammonium nitrate for use as high 

 explosives. Picric acid costs about 185I. per ton to 

 make, ammonium nitrate about 50!., and T.N.T. 

 about loot, per ton ; the high cost of picric acid 

 mean?;, of course, limited production. A mixture of 

 eightv parts of ammonium nitrate with twenty parts 

 of T.N.T. , known as amatol, was introduced early 

 bv the Research Department at Woolwich as being 

 about ::; per cent, more powerful as a high explosive, 

 less hrisant, and more difficult to detonate, and, of 

 course, far less costly to manufacture. The course 

 of the war has been marked by continued progress 

 at the hands of our research chemists in the prepara- 

 tion and application of amatol ; the growing apprecia- 

 tion of the merits of this material led to the dis- 

 continuance of the manufacture of picric acid in this 

 countrv last summer, to the adoption of amatol in 

 place of picric acid as the American standard high 

 explosive, to the approaching elimination of picric 

 acid from the Italian militarv programme, and to the 

 replnrement, in the main, of picric acid by amatol in 

 the French service. 



A very pertinent question arises in connection with 

 the fact that our production of the chemical materials 

 needed for a great European war was negligibly 

 small in 1914 and has gradually attained satisfactory 

 dimensions. We know that the great chemical fac- 

 tories of Central Europe could divert their peace pro- 

 duction of chemical products to a war output at very 

 short notice. None of these huge installations requires 

 much time for the design and construction of chemical 

 plant for new purposes ; all possess a series of 

 standard items of equipment which can be fitted 

 together rapidlv to form a piece of plant capable of 

 use for throwing anv ordinar\- laboratorv operation 

 into large-scale practice. Stills, condensers, pressure 

 vess'Ms, filter presses, cooling arrangements of coils, 

 and the like, are available in standard sizes and with 

 standard fittings in such a manner that the installa- 

 tion on a works scale of a laboratorv operation is 

 deprived of its most formidable difficulties. The 

 question ^vhich demands an answer is whv. when 

 the German works were in existence and could attain 

 a war nroduction so quicklv. were the Allied nations 

 gi\ien time graduallv to develop their war production 

 of explosives, noxious materials, etc., from nothing? 

 The Question is best answered bv an example. 



In July. iqtr. the Germans first used against the 

 Allies a new offensive material. /3^-dichloroethvl sul- 

 phide. fCH,Gl.CH,)S, and with verv great success. 

 This substance, the so-called "mustard gas," has but 

 little odour, and exposure to it causes comparatively 

 fe^- fatalities: inhalation of, or contact with, its 

 vapour gives rise to acute pneumonia when inhaled, 

 to the production of oainful sores, and to temporary, 

 or even permanent, blindness. Whilst, as has been 



NO. 2585, VOL. 103] 



stated, the actual mortality is low, and the use of the 

 substance may to this extent be described as humane, 

 the casualties produced are very numerous; slight 

 exposure to a material so toxic and so difficult to 

 detectleads, in general, to six weeks in hospital. The 

 preparation of ^/3-dichloroethyl sulphide was described 

 by Victor Meyer in 1886, and involved the several 

 operations indicated by the following set of 

 equations : — 



(1) CH.,:CH, + HC10 = CHsClCH50H. 



(2) 2CH..C!.CH,.OH + Na2S = (HO.CHj CHo)2S + 2NaCl. 



(3) (H0.CH2.CH.,).,S + 2HC1 = (CH2C1.CH,).,S.4-2H„0. 



When it is realised that operation No. i is difficult, 

 and that the products of reactions (1) and (2) are 

 soluble in water, it will be understood that no small 

 difficulties must present themselves in the manufac- 

 ture of ^/3-dichloroethyl sulphide by this process on a 

 large scale. The examination of the German product 

 made it quite clear, however, that the process of 

 manufacture adopted was that indicated by the above 

 set of equations; the over-all yield of product is 

 perhaps 40 to 60 per cent, of the theory. In view of 

 the difficulties of manufacture, it was fairiv certain 

 that no chemical installation for its production could 

 be established under the control of the Allies withm 

 any reasonable time; the Central nations thus sup- 

 posed that they held the monopoly of a very powerful 

 instrument of war. 



Most British organic chemists were, T thmk, amazed 

 at the method of production adopted by the German 

 manufacturers; to apply such a technically cumbrous 

 process for the manufacture of so simple a compound 

 seemed quite irrat'onal. By the end of January, 1918, 

 a process for making ^SjS-dichloroethyl sulphide had been 

 worked out in the British laboratories which con- 

 sisted of the reaction expressed by the following 

 equation : — 



2CH, : CH= + SX1,=(CH,CI.CH,),S+S. 

 The yield obtained in the laboratory was 98 to 99 per 

 cent, of that theoretically possible. The new method 

 was communicated to France and .'\merica, and in- 

 stalled bv the three great Allies on a large scale; at 

 the conclusion of the armistice the available daily 

 production of mustard gas bv the .Allies was equal to 

 the monthly production of the Central nations. 



The answer to the question iust put is now avail- 

 able. The German Chemical Service was inefficient; 

 the scientific chemists under its control were incom- 

 petent. 



The Allied production of mustard gas h.id a poten- 

 tialitv of the order of thirty times as great as that of 

 the German ; the cost of the German material was of 

 the order of thirty times as great as that of our pro- 

 duct. Cost of production under the conditions prevail- 

 ing for this p.nrticular material means, in the end. 

 expenditure in labour; that we were able to produce 

 at something of the order of one-thirtieth of the cost 

 of the German production means that by the allocation 

 of the same quantity of raw materials we could secure 

 thirty times the output. The relative strain on the 

 productive resources of the .Mlies and the Central 

 nations caused bv the demand for a certain quantity 

 of mustard gas is measured, roughly, by the ratio of 

 one to thirty. 



Whilst many instances similar to that of mustard 

 gas might be quoted to show that Germany has been 

 badlv served by her scientific men during the war. it 

 would be difficult to overrate the effects of the skill 

 and perseverance <^xhibited bv the German chemical 

 manufacturer. The f-ommand of £?reat and long- 

 ostnblished factories for fine chemical manufacture 

 enabled the German technologist to throw fault\' 

 academic projects rapidly into large-scale production. 

 The cost — namely, the strain on national resources — 



