Manchester Memoirs, Vol. xlii. (1898), No. 0. 27 



connection with the vapour chamber in which the 

 thermometers were placed. 



The execution of this was undertaken by Mr. Foster, 

 who has produced a very beautiful instrument, the mercury 

 being re-evaporated in apparatus belonging to Dr. Schuster 

 by his assistant, Mr. A.T. Stanton. The readings are easily 

 taken, and verified to the ten-thousandth of an inch. 



The correction on the thermometer for 32*^F. was 

 obtained in the usual way ; but as there was no ready 

 means, as with the higher temperature, of testing the 

 scale of the thermometer for two or three degrees above 

 32^^, this correction could only be made by comparison 

 with the thermometer already compared with the air 

 thermometer, and these comparisons Dr. Schuster kindly 

 allowed to be made in the physical laboratory. 



The corrections of the thermometers on account of the 

 pressures in the thermometer chambers were also deter- 

 mined, while the limits of error, owing to the slight excess 

 of the low temperature over 32^, were carefully considered 

 and defined. 



The question as to what should be done in the way of 

 rejecting trials was also a subject of first consideration. 

 It was certain that in such a research accidents must occur, 

 and it was necessary to have some rule so as to prevent any 

 sorting of the trials. It was therefore arranged to reject 

 all trials in which there was definite evidence, either during 

 the trial or in the results, of uncertainty in any one of the 

 measurements to which no definite limits could be assigned, 

 without regard to the apparent consistency of the results, 

 and to retain all other trials. 



After the conclusion of the trials, on opening the 

 brakes, an estimate of the wear of the metal was made, 

 from which estimates of the possible absorption of work 

 in disintegrating the metal and of the production of heat 

 in oxidizing the metal were obtained. 



