482 Colonel Sir Frederic L. Natlian [Jan. 29, 



fngalling, the skeins were drowned as rapidly as possible in a cascade 

 of water, the object being to remove the rest of the free acid. The 

 final purification was effected by immersing the skeins for about three 

 weeks in running water, boiling for a few minutes in an alkaline 

 solution, and finally washing for a few days in flowing water. 



In all that concerned the actual process of nitration, Abel followed 

 von Lenk, but instead of using skeins of long staple cotton, he 

 introduced the use of cotton waste from the spinning mills, suitably 

 cleaned : and after the free acid had been removed in the prehminary 

 drowning, the guncotton, still in the same physical condition as the 

 cotton waste from Avhich it had been produced, was reduced to a fine 

 state of division in a beating-engine. The effect of this important 

 modification was to remove the last traces of " free acid," and of 

 unstable bodies, so that the prolonged washing in cold water could 

 be dispensed with, and at the same time, a much more stable product 

 be obtained. 



Cotton fibre is of a tubular structure, and as long as these tubes 

 exist in long lengths, the impurities in the interior of the tubes, 

 derived from the evaporated juices of the cotton plant, and more or 

 less affected by the nitration process, are extremely difficult of removal. 

 Xot only is the cotton in the form of long tubular fibres, but these 

 fibres are themselves matted and entwined to such an extent that the 

 former process of washing in running water even failed to remove 

 impurities from amongst the bundles of fi])re. 



The operation of pulping introduced by Abel, breaks up both 

 the bundles of fibre and the fibres themselves, reducing the latter to 

 short lengths or destroying them altogether by crushing. In this 

 fine state of division the removal of impurities is much more readily 

 effected by washing. 



The manufacture of guncotton by the von Lenk-Abel process 

 was commenced in this country about 18G5. Foreign countries took 

 it up in quick succession, and the process was the one universally 

 followed for the next 40 years. Some modifications of the nitration 

 process were made towards the end of that period, in one case in the 

 direction of dipping larger charges of cotton waste, and of allowing 

 them to remain in the original acid mixture until nitration was com- 

 pleted, and then transferring the whole contents of the nitrating pan 

 into the acid centrifugal : in another case the nitration process was 

 actually carried out in the centrifugal itself. 



In 1905, however, an entirely new system of nitration, hereafter 

 referred to as the " displacement process," was invented by Messrs. 

 Thomson, of the Royal Gunpowder Factory, and this process has 

 been perfected and has entirely replaced the pot system of nitration 

 there, and at Nobel's Explosives Factory at Ardeer, in Scotland. 

 It is also being adopted at other factories both in this country and 

 abroad. 



The nitration of the cotton waste is carried out in shallow circular 



