REPORT ON THE PRESSURE ERRORS OF THE THERMOMETERS. 



37 



By means of this apparatus I have measured directly the rise of temperature, produced by pressure, 

 in a great variety of substances. Some of my results will be found in the Tree. R S. E., May 1881. 

 I do not insert them here, but content myself with mentioning that they fully bear out the results 

 already obtained with vulcanite and lard by means of the larger apparatus. 



One or two other remarks as to the behaviour of the thermometers under pressure may 

 conveniently be inserted here, as they serve to explain some of the results obtained during the 

 expedition. 



On the first occasion on which one of the thermometers gave way, we were much surprised at 

 the loudness and musical quality of the sound produced. The whole mass of iron and steel vibrated 

 like a bell in consequence of the (comparatively slight) sudden relaxation of pressure. On another 

 occasion, just as a pressure of three and a half tons had been reached, the whole apparatus gave a 

 strong, protracted musical sound, which continued until the screw-tap was opened. 



This was 



