MECHANICAL STRETCHING OF LIQUIDS. 
357 
The temperature of part of the vessel and its contents is now raised. This causes 
the liquid to expand and fill the whole ; if the rise of temperature continued the 
vessel would burst; but before the pressure becomes dangerously great the liquid is 
cooled again by means of ice-cold water. It now, however, adheres so firmly to the 
walls of the vessel that, though cooled, it cannot contract, and it remains extended or 
stretched, tugging at the walls until at last, as the cooling proceeds, the tension 
becomes so great that the liquid lets go its hold, and releases the glass walls with a 
loud metallic click, and itself springs back to the smaller volume appropriate to the 
temperature and to the pressure of its saturated vapour. 
Fig. 1. 
Whether the cohesion of the liquid for itself or its adhesion to the glass is first 
overcome is not decisively determined, but all indications point rather to the latter 
than to the former supposition. 
The form and dimensions of the vessel used in my experiments are given by the 
accompanying diagram, v r hich is drawn to the scale of one quarter. 
