upon Gun-fowder , &c. 273 
If this were a queftion merely fpeculative, it might not be 
worth while to fpend much time in the difcuffion of it ; but as 
it is a matter upon the knowledge of which depends the deter- 
mination of many important points refpedting artillery, and 
from, which many ufeful improvements may be derived, too 
much pains cannot be taken to come at the truth. Till the 
manner in which powder takes fire, and the velocity with which 
the inflammation is propagated, are known, nothing can with 
certainty be determined with refpecl to the bell: form for the 
chambers of pieces of ordnance, or the mod: advantageous, 
fituation for the vent; nor can the force of powder, or the 
strength that is required in different parts of the gun, be afcer- 
tained with any degree of precifion.. 
As it would be eafy to determine the bed: fituation for the 
vent from the velocity of the inflammation of powder being 
known, fo on the other hand I had hopes of being able to come 
at that velocity by determining the effeft of placing the 
vent in different parts of the charge ; for which purpofe the.: 
following experiments were made. 
