Mr. Mitchell on the Burning of the Fuses of Shells. 49 



gested that some fuses should be burnt at the Mount, or at Madras, 

 under a receiver, exhausted until the barometer stood at the Banga- 

 lore mean height, or about 27 inches. This, however, it was not 

 found convenient to do ; but, as an equally satisfactory way of test- 

 ing the accuracy of my conclusions, a small number of fuses were 

 prepared and burnt at St. Thomas's Mount, at Bangalore, and at 

 two different altitudes on the Neilgherry Hills, as will be seen by 

 the annexed copy of an official memorandum; and although this ex- 

 periment was too limited to enable us to compile a scale of the pro- 

 bable times a certain length of fuse composition would burn at given 

 altitudes, it amply proves the fact that combustion is retarded at 

 considerable elevations. 



" Memorandum of an experiment to ascertain whether the atmo- 

 sphere influences the burning of fuses : — 



" Eighteen 8-inch fuses, made of the same description of wood 

 (Congo), were filled with composition made for the purpose. The 

 same man drove the whole on the morning of the 2nd August 1849, 

 using the same mallet and drifts. Six of the fuses were burnt at the 

 Mount, six at Bangalore, and six on the Neilgherry Hills ; all in the 

 presence of artillery officers ; the result is shown below " : — 



The writer attributes the result to the rarity of the atmospheric 

 air, and of its constituent oxygen at the higher stations. 



• The fuses thus marked accidentally ignited at both ends. 



Phil. Mag. S. 4. Vol. 10. No. 63. July ?l855. E 



