III. On the measurement of pressures by the crusher-gauge

The object of the experiments, the results of which are given in this paper, was to compare the indication of pressure (produced by the firing in a closed vessel of a gunpowder) by the crusher-gauge with a simultaneous estimation of the same pressure by another and simple method. This latter consisted in ascertaining the weight which was equal to the maximum pressure of the gases of the fired cordite (the smokeless gunpowder used in these experiments) acting on a valve closing gas-tight an opening in the explosion-vessel of area small enough to allow of the use of weights of manageable amount, not so small a fraction of the unit of surface (1 sq. in.) as to have to use a very large multiplier. Within the explosion-vessel, on the top of which were the valve and weights, was placed the crusher-gauge, the firing of the charge of cordite giving the two indications of pressure.