ON THE ADIABATIC RELATIONS OF ETHYL OXIDE. 
171 
and the experimental tube was then screwed into the pressure apparatus by means 
of the iron cap for the purpose. 
It was found that if mercury entered the space between the rod, D (tig. 2), and 
the internal wall of the experimental tube, A, it could not be removed by tapping, 
after the apparatus had been set up ; and also that it interfered with the vibrations 
of the rod. Hence it was necessary to take precautions to prevent mercury entering 
the tube so far as to touch the end of the rod. 
Fig. 2. 
The experimental tube having been placed in position in the pressure apparatus, 
and the cap tightly screwed on, the temperature was raised to a given point, 
determined by the amount of ether left in the tube ; tlie pressure was then raised by 
turning the screw of the pressure apparatus A (fig. l), and when the end of the screw 
came in contact with the drawn-out capillary end of the experimental tube, C (fig’. 3), 
whicli is there shown unsealed, it broke it. It was necessary so to regulate the 
temperature of the ether that only a little escaped when the capillary end was 
broken. If the pressure in the interior were too great, too much ether escaped ; it 
too small, cold mercury entered, and came in contact with the internal rod. After 
some ])raciice it was found possible to arrange the apparatus successfully nearly every 
z 2 
