To make a test, after the bottle full of water has been fastened under the support, C D, the cock, s, is opened and the liquid with which the small reservoir, R, has been filled flows through an aperture above the mouth of the bottle and rises in the tube, a b.  When its level reaches the division, O, the cock, s, is closed.  The bottle and its prolongation, a b, are now exactly full of water without any air bubbles.

The pump is actuated, and, in measure as the pressure rises, the level of the liquid in the tube, a b, is seen to descend.  This descent measures the expansion or flexion of the bottle as well as the compression of the water itself.  When the pressure is judged to be sufficient, the button, n, is turned, and the air compressed by the pump finding an exit, the needle of the pressure gauge will be seen to redescend and the level of the tube, a b, to rise.

If the glass of the bottle has undergone no permanent deformation, the level will rise exactly to the zero mark, and denote that the bottle has supported the test without any modification of its structure.  But if, on the contrary, the level does not return to the zero mark, the limit of the glass’s elasticity has been extended, its molecules have taken on a new state of equilibrium, and its resistance has diminished, and, even if it has not broken, it is absolutely certain that it has lost its former resistance and that it presents no particular guarantee of strength.

The vessel, A B, which must be always full of water, is designed to keep the bottle at a constant temperature during the course of the experiment.  This is an essential condition, since the bottle thus filled with water constitutes a genuine thermometer, of which a b is the graduated tube.  It is therefore necessary to avoid attributing a variation in level due to an expansion of the water produced by a change in temperature, to a deformation of the bottle.

The test, then, that can be made with bottles by means of the elasticimeter consists in compressing them to a pressure of ten atmospheres when filled with water at a temperature of 25 deg., and in finding out whether, under such a stress, they change their volume permanently.  In order that the elasticimeter may not be complicated by a special heating apparatus, it suffices to determine once for all what the pressure is that, at a mean temperature of 15 deg., acts upon bottles with the same energy as that of ten atmospheres at 25 deg..  Experiment has demonstrated that such stress corresponds to twelve atmospheres in a space in which the temperature remains about 15 deg..

In addition, the elasticimeter is capable of giving other and no less useful data.  It permits of comparing the resistance of bottles and of classifying them according to the degree of such resistance.  After numerous experiments, it has been found that first class bottles easily support a pressure of twelve atmospheres without distortion, while in those of an inferior quality the resistance is very variable.  The champagne wine industry should therefore use the former exclusively.