AT KEW OBSERVATORY AND THEIR DISCUSSION. 



465 



included the rest, but half-weight only was attached to each of two experiments in 

 which the temperature was 70. The treatment applied to these groups was the 

 same as for aneroids Nos. 2 and 3. Aneroid No. 1 was somewhat erratic almost from 

 the start, and the results from it are not reproduced : they showed clearly enough 

 the same general phenomena as in the others. The results for aneroids Nos. 2, 3, 

 and 4 are given in Table XIX. The temperatures quoted are the means for the 

 colder and hotter groups. 



TABLE XIX. Corrected Errors, influence of Temperature. 



The experiments being numbered in chronological order, the arithmetic means of 

 the experiment numbers in the several groups were, for aneroids Nos. 2 and 3, 

 colder 38, hotter 37 ; for aneroid No. 4, colder 24, hotter 27. This alone would 

 suffice to show that the phenomena cannot be ascribed to any gradual change in the 

 aneroids. 



24. I next consider the possible influence of temperature on the fall of reading 

 at the lowest pressure. Taking the 16 earliest experiments in which pressure was 

 reduced at the normal rate to 2 1 inches, and then maintained steady for 1 minutes, 

 I divided them into four groups, as follows : 



Group I., Experiments Nos. 6, 7, 18, 19. 



II., 29, 30, 31, 32. 



III., 34, 36, 39, 40. 



IV., 41, 42, 43, 44. 



Temperature did not vary much between individual experiments of the same 

 group. 



VOL. CXCI. A. 3 O 



