202 MUNROE-HOWELL— PRODUCTS OF DETONATION OF TNT. 



fact that the Bureau of Mines Experiment Station possesses a Bichel 

 Pressure Gage equipment with proper laboratory accessories which 

 it has long made use of in its tests of explosives to determine their 

 " Permissibility " and for other purposes, and a force experienced 

 in their use ; and that TNT is now readily accessible and possesses a 

 special interest, it has been deemed proper to make a special investi- 

 gation of the products of detonation of TNT. As the investigation 

 will necessarily be somewhat prolonged we are presenting here prac- 

 tically a progress report giving the preliminary results. 



The TNT at command from the war surplus gave a solidification 

 point of 80.2°, and a nitrogen percentage by the Orndorfif method of 

 18.14 and by the Dumas method of 18.32 both S.P. and N-content 

 being used as criterions of purity, and the N-content being also used 

 as a ready check on the completeness of the recovery of the products. 



The Orndorff method of determining nitrogen devised by Prof. 

 Orndorff of Cornell University and as yet unpublished, is briefly a 

 modification of the Kjeldahl method in which red phosphorus and 

 hydrogen iodide, together in some instances with iodine, is used as 

 the reducing agent, and cupric sulphate, sodium sulphate and sul- 

 phuric acid as the digestion agent. This method has been quite 

 generally used during and since the war and is much approved. 

 The method gives quite concurrent results on explosive substances 

 and from general considerations of all the circumstances it is be- 

 lieved to give results to about the same degree below the truth that 

 the Dumas method does above. 



The Bichel Pressure Gage equipment of the Bureau of Mines is 

 described, with illustrations, on pages 103-109 of Bureau of Mines 

 Bulletin 15^" and the procedure followed in its use on pages 30-32 of 

 Bureau of Mines Technical Paper 186.^^ In early tests of explosives 

 detonations were made in lead bombs enclosed in the gage after the 

 manner described by Poppenberg and Stephan but this was found to 

 injure the gage and alter its volume, hence the method was long 

 since abandoned. A recent recalibration of both the 15- and 20-liter 



10 " Investigations of Explosives Used in Coal Mines," Clarence Hall, W. 

 O. Snelling, and S. P. Howell. 1912. 



11 " Method for Routine Work in the Explosives Physical Laboratory of 

 the Bureau of Mines," S. P. Howell and J. E. Tiffany. 1918. 



