64 Scientific Proceedings, Royal Dublin Society. 



Throughout the coejEEcieut of the expansion of glass is 



gf = 2-4 X lO-\ 



k = compression modulus of glass = 4 x 10° atm. 



n = torsion modulus of glass = 3 x 10' atm. 



Table. 



In making the observations on the temperatures, the tubes were set in 

 a large beaker of water. The temperature at which the tube became filled 

 was then roughly determined by warming the beaker up very slowly till the 

 bubble in the tube disappeared. The tube was then allowed to cool and the 

 bubble to reappear. The beaker was again raised to a temperature one 

 degree below that at which it was expected the bubble would disappear. 

 The beaker was kept at this temperature for five or ten minutes, and the 

 water within it was kept in motion to secure a fairly uniform temperature. 



