466 



DE. C. CHREE, EXPERIMENTS ON ANEROID BAROMETERS 



Table XX. gives the mean temperature for each group, and the mean falls of 

 reading at the intervals 2, 4, 6, 8, and 10 minutes after the lowest pressure, 

 21 inches, was reached. To avoid decimals, the unit chosen is the ^-Q of an inch. 



TABLE XX. Fall at Lowest Pressure (21 inches), unity = '0025 inch. 



The results in the last two groups for aneroid No. 1 are omitted as not comparable 

 owing to repair of the instrument with the earlier ones. 



In Table XX. there is no certain indication of any temperature effect. 



In the special temperature experiments, Nos. 52 to 55, the observed mean falls 

 in the colder and hotter groups were as follows : 



TABLE XXI. Fall in 10 minutes at Lowest Pressure (21 inches) in inches 



(Experiments 52 to 55). 



There being only two experiments in each group, it would be unsafe to base on 

 this any more definite conclusion than that if there is any temperature effect it is 

 certainly not large. 



25. The influence of temperature on the differences of the descending and 

 ascending readings next calls for consideration. The experiments bearing most 

 directly on this point are the special ones, Nos. 52 to 55. The results derived from 

 them are given in Table XXII., unity representing 1 inch. 



