298 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1908. 



before a distinct coloration in the tube is observed. This method com- 

 pares very favorably with all others. 



As I frequently mentioned, the duration of the heat test is prac- 

 tically halved by a rise in temperature of 5° C, and Will has con- 

 firmed this by proving that the volume of gases evolved is doubled 

 at the same time. This is, however, only correct for temperatures 

 above 45° C, the critical point for nitrocellulose. BeloAv 40° C. the 

 durability of an explosive properly prepared with it increases exceed- 

 ingly rapidly, and it may be safely assumed that under 20° C. its 

 stability is permanently assured. 



This contention has been proved in practice. The author does not 

 know of a single authenticated instance of decomposition in an ex- 

 plosive magazine where the temperature has been kept within the 

 permissible limit. 



This simple precaution was, however, neglected in a good many 

 instances by both naval and military authorities. It was and still is 

 the practice in men-of-war to arrange the ammunition stores and 

 poAvder magazines in close proximity to boilers and engines, fre- 

 quently without any ventilation, whilst at times explosives of all 

 kinds are stored together. Fourteen years ago "■ the author discussed 

 this arrangement, and drew attention to the dangers arising there- 

 from. A dozen explosions on men-of-war and a disaster like that on 

 the Jena occurred before an alarm was raised, and now all navies are 

 hurriedly installing refrigerating apparatus. This is all very well 

 as far as it goes if the machinery does not break down at the critical 

 moment ; but can not designers of war ships find another place for 

 ammunition ? Why go to the length of all sorts of precautions when 

 it should not be impossible to remove the cause of deterioration 

 altogether ? 



This misplacing of ammunition stores is only slightly mitigated by 

 the fact that twenty years ago the manufacture of smokeless powders 

 had only just begun, and nobody knew much about them. Worse 

 than this, however, was the action of many governments in at once 

 erecting their own powder works, without any experience in the manu- 

 facture of nitrocompounds to go upon, and relying entirely on Avhat 

 private manufacturers cared to show them, and on Avhat they them- 

 selves could find out by experiments. Some of their powders made 

 fifteen and tAventy years ago are still in service, and are noAV the 

 objects of suspicion. 



It is, nevertheless, not fair to throw the whole of the blame on the 

 explosive charge. How would the priming and detonating composi- 

 tions used in gun charges and shells behave under unfavorable cir- 

 cumstances? Fulminate of mercury, potassium chlorate, sulphur, 

 antimonypentasulphide, picric acid, and other chemicals are con- 



" Journal of the Society of Chemical Industry, 1894, p. 583. 



