PRECIS 
V 
AND 
TRANSLATIONS. 
“REYUE D’ARTILLEKIE.” 
REGISTERING PRESSURE-GAUGE APPLICABLE 
TO ORDNANCE. 
BY 
LIEIJT.-COLONEL F. E. B. LORAINE, late R.A. 
No. 19 of the Comptes rendm of the Academie des Sciences , relative to its sitting- 
on the 11th May, 1891, gives an account by Yieille of a registering pressure- 
gauge applicable to ordnance :— 
We have sought to determine the law of development of pressures in the 
bores of guns up to the moment of their maximum by a development of the 
ordinary crusher-gauge. 
This result has been obtained under conditions of quite unexpected simplicity 
by the simple provision of a small smoked plate, less than a square centimetre 
(•155 of a square inch) in area at the head of the crusher. A vibrating lever, 
during its movement, traces its course on the smoked plate. The lever is fixed 
on the plate, but is released automatically by the first movement of the crusher 
piston. This arrangement is equally suited to the powder chamber, or to the 
bore in front of the driving ring of the projectile. 
The value of the period of vibration of the lever being known, it suffices to 
read with a micrometer the lengths intercepted by the undulations upon the axis 
of the figure traced on the smoked plate, in order to obtain the value of the 
pressure in function of the time. 
The general results, derived from a study of more than 150 tracings, obtained 
in naval guns of 14"-5, 10"'6, 9"‘4, 6"-2, and 5"*5 calibre, and in military 
pieces of 3"'5 and 6" calibre, are as follow :— 
1°—The crusher apparatus placed in the powder chamber works statically, 
that is to say, there is equilibrium at every moment of the crush between the 
motive pressure and the resistance of the cylinder. This result has even been 
obtained with powders much more violent than the service ones. It follows 
therefore that not only does the final resistance of the crushed cylinder measure 
properly the maximum pressure, but that, by referring to the table of the static 
compression of cylinders, we may deduce from the compression observed at every 
6. VOL. XIX. 
