EXPLOSIVES 379 



vary. In the United Kingdom the Explosives Department of 

 the Home Office prescribes the conditions which must be obeyed. 



The following account of the manufacture of gun-cotton is 

 chiefly taken from a lecture given by Mr. William Macnab 

 before the Institute of Chemistry of Great Britain and Ireland 

 in February, 1914. 



In laying out explosives works it is necessary to distinguish 

 the danger area from the non-danger area. In the latter, boilers, 

 engines, acid stores, and other departments may be arranged 

 in any manner found to be most convenient, but in the former 

 where the manufacture of the explosive is carried out the case is 

 quite different. '' The object of the restrictions is to allow only 

 limited quantities of explosive material and a limited number of 

 work-people in one building at a time, and further to place the 

 different buildings at such distances from each other, or surround 

 them by protecting earth mounds (Fig. 131), that in the event of 

 an explosion the effect is localised as much as possible, and the 

 explosives in the adjacent buildings are not ' set off.' ' Special 

 precautions are taken to prevent the accumulation of dusty 

 explosive matter, and scrupulous cleanliness is enforced. No 

 naked iron or steel is allowed where the more explosive materials 

 are treated ; the workers have to wear shoes containing no iron 

 or steel nails ; and in order to prevent the introduction of grit 

 from the outside those entering the building temporarily have 

 to slip on large shoes which are kept at each building specially 

 for this purpose. Everyone on entering an explosive works has 

 to give up any matches he may have in his possession ; the work- 

 people have to wear special outer clothing without pockets ; and 

 women have to fix their hair without pins which might possibly 

 fall in among the explosives with which they are working. 



The lighting of the buildings is nearly always electrical, and 

 where motive power is required, it is usually supplied by electric 

 motors placed outside the building. 



It is not permissible to use a house for a different operation 

 from that for which it is licensed without special authorisation. 

 Serious penalties follow the breach of the terms of the licence 

 under which the factory is allowed to work, and surprise visits 

 from the Inspectors of Explosives help to maintain a good state 

 of discipline. 



The manufacture of gun-cotton and the other forms of nitro- 

 cellulose is carried out in the first stages in the non-danger part 



