1021] 



on War Development of Explosives 



363 



gave much promise from the start. They were found to possess the 

 requisite degree of inertness and insensitiveness to enable them to 

 withstand set-back on firing from a gnn, to have a high rate of 

 detonation, and when detonated in a shell, as was done first in March 

 1915, to give evidence of the required violence necessary to fragment 

 the shell. 



The first mixture (later termed amatol 40/60, these being the 

 proportions of ammonium nitrate to T.N.T.) was capable of being 

 poured as a thick porridge into shell, and so presented few difficulties 

 for large-scale production. This was at once followed up by similar 

 experiments with a still greater proportion of ammonium nitrate, up 

 to that which is practically the theoretical one for complete com- 

 bustion of all the carbon of the trinitrotoluene to carbon dioxide, 

 and of all the hydrogen in both substances to water. This explosive, 

 amatol 80/20, was fired in a shell in April 1915, and gave excellent 

 results. Its explosive properties, as regards insensitiveness, stability, 

 and tests for power, were satisfactory, and it was almost immediately 

 approved as a Service explosive. 



Amatol 80/20. — The development of amatol 80/20 was slower. 

 Prepared originally on the large scale by bringing together the finely 

 powdered ingredients in a mixing machine, or by grinding them 

 under edge-runners, 80/20 amatol was ultimately most readily pro- 

 duced by taking advantage of the plasticity of the heated mixture due 

 to the trinitrotoluene melting. Hydraulic presses were used for 

 introducing the powdered or ground explosive into shell ; for the 

 plastic 80/20, a worm feed was found expeditious and rapid. 



In the course of the manufacture of the enormous quantities of 

 these substances many points of interest and of difficulty arose, which 

 were solved by the assistance of more and more scientific investigators. 



The following tables give some data on the explosive properties 

 of the amatols in comparison with some other explosives : — 



Heat op Detonation and Gases Evolved. 



Calories per gram Total gases 

 (water gaseous) c.c. per gram 



Picric acid .... 914 



Vol. 



