February 24, 192 1] 



NATURE 



833 



plant for 60 tons, and replaced a pot installa- 

 tion by one using the Thomson process. The 

 same change was effected at Bracqueville, and 

 a Selwig- plant was installed at Bergerac. The 

 nitro-cotton, after washing, was stabilised by boil- 

 ing with water, pulped, and dried to 30 per cent, 

 moisture. Two varieties were made, CPj with 

 II per cent, of nitrogen, soluble in a mixture of 

 alcohol and ether, and CPo with 13 per cent, 

 of nitrogen, insoluble in that mixture. 



Poudre B was made by masticating the requisite 

 proportions of these two varieties with a mixture 

 of alcohol and ether, pressing into filaments, and 

 drying. This was carried out at Le Bouchet, Pont- 

 de-Buis, Ripault, Saint Medard, Sevran-Livry, 

 Bergerac, and Toulouse. The maximum produc- 

 tions in tons per day from these works were 10, 

 48, 60, 140, 35, 60, and 130 respectively. Private 

 industry furnished a maximum of 20 tons of bal- 

 listite (gelatinised nitro-cotton with nitroglycerin); 

 The total production of Poudre B in France from 

 1914 to 1918 amounted to 306,693 tons, and 

 117,000 tons were during this period imported 

 from America. 



The manufacture of nitro-explosives was accom- 

 panied by strenuous endeavours to improve the 

 methods of production and to replace these sub- 

 stances by others less difficult to produce. The 

 75-mm. shells, for example, were filled with am- 

 monium nitrate and dinitronaphthalene ; chlorates 

 and perchlorates were introduced for filling hand 

 grenades ; and experiments were made with liquid 

 air for charging aeroplane bombs. 



The nitro-bodies picric acid and trinitrometa- 

 cresol could be manufactured by known methods, 

 but the production of trinitrotoluene, xylite, dini- 

 trophenols, and mono- and di-nitronaphthalenes 

 was introduced during the progress of the war. 

 These explosives were used both alone and in the 

 form of mixtures. 



Three methods are available for the manufacture 

 of picric acid (trinitrophenol) : nitration of phenol 

 in presence of sulphuric acid by nitric acid orsodium 

 nitrate ; chlorination of benzene, transformation of 

 monochlorobenzcne into dinitrochlorobenzene 

 I, 2, 4, saponification of this with formation of 

 dinitrophenol, and trinitration of the latter; direct 

 oxidation and nitration of benzene with nitric acid 

 and mercury. The method of direct nitration alone 

 was used. The second method was in use in 

 Germany prior to the war, but as it required the 

 use of pure chlorine it was not suited to French 

 needs. Nevertheless, 1000 tons of chlorine were 

 ordered from America in order to commence pro- 

 duction in France. After the German gas attack 

 of April 22, 191 5, on the Belgian front, this 

 chlorine was devoted to experiments on the new 

 method of warfare. In the meantime the produc- 

 tion of phenol had increased, and there was no 

 longer any point in making use of the method of 

 chlorination. The yield by the third method was 

 poor (140 of picric acid per 100 of benzene, as 

 compared with 190 with phenol), and the recovery 

 of the mercury was difficult. The latter was im- 

 portant in view of the pressing need of mercury 

 NO. 2678, VOL. 106I 



for the manufacture of fulminate. Picric acid so 

 prepared may also contain small amounts of 

 mercury picrate, which renders it very sensitive 

 to shock. 



There were three picric acid factories in opera- 

 tion before the war. Several chemical and dye 

 factories in the Lyons district were requisitioned, 

 including one of the Badische firm. State fac- 

 tories were also erected. Some of these factories 

 were destroyed by explosions. The total pro- 

 ductions of picric acid and trinitrotoluene, in tons 

 per day, were as follows : — 



Production 0/ Trinitrotoluene in metric tons per 

 day. 



August, 1914, 031 January, 1917, 667f (maximum 



August, 1915, 893 January, 1918, 2402 



August, 1916, 55-87 



Production of Picric Acid in metric tons per day. 



August, 1915, 050 July, 1917, 1661 (maximum) 

 January, 1916, 1V95 January, 1918, 5886 

 January, 1917, 14547 



Lack of cresol led to the use of dinitrophenol, 

 made by nitrating phenolsulphonic acid. Picric 

 acid was also formed, but as a mixture of the 

 two substances was finally used, this was im- 

 material. The preparation by the nitration of 

 chlorobenzene led to the installation of electrolytic 

 chlorine apparatus producing 20 tons of chlorine 

 per day. 



The explosive schneiderite was used in large 

 quantities, and was prepared by triturating in 

 mills a dry mixture of 88 parts of am- 

 monium nitrate and 12 parts of dinitro- 

 naphthalene. The ammonium nitrate was prepared 

 to some extent by double decomposition of 

 accumulated stocks of Norwegian calcium nitrate 

 (for agricultural purposes) with ammonium 

 sulphate, by neutralising nitric acid with ammonia 

 solution, and by the interaction of ammonium 

 sulphate and sodium nitrate according to a process 

 worked out by M. Fosse, of Bordeaux, and by 

 M. Danne, of Gif. Nearly all the ammonium 

 nitrate, however, was imported from Norway at 

 the rate of 200 tons per day. 



Chlorate and perchlorate explosives were also 

 manufactured. Paraffined ammonium perchlorate 

 was tried for filling 75-mm. shells, but proved too 

 sensitive to shock. It was, however, extensively 

 used for trench-mortar bombs, hand grenades, and 

 aeroplane bombs. Sodium chlorate and a mixture 

 of 61-5 parts of ammonium perchlorate, 30 

 of sodium nitrate, and 8-5 of paraffin were 

 used. The chlorates and perchlorates were made 

 electrolytically at Cheddes, Vonges, Castres, and 

 Grenoble, the production being 79 tons of am- 

 monium perchlorate and 77 tons of sodium 

 chlorate per day. 



Many new products were made. Mustard gas, 

 known as "yperite," was produced at the rate of 

 6 tons per day at the signing of the armistice, 

 and plant for the manufacture of 12 tons per day 

 was ready to be put into operation. A daily pro- 

 duction of 24 tons was planned. I^iquid nitrogen 



