AT KEW OBSERVATORY AND THEIR DISCUSSION. 



457 



Whilst I regard the present experiments as throwing much fresh light on the 

 subject, it will, I hope, be clearly understood that I do not profess to have established 

 a complete physical theory, by the aid of which one can foretell the exact behaviour 

 of an aneroid under any arbitrary set of conditions. 



Fall of Reading at the Lowest Point. 



16. In the 24 experiments described in 7, readings were taken at 2-minute 

 intervals during the 10 minutes' stoppage at the lowest pressure. It was soon 

 obvious that the fall in a given time was at least approximately proportional to the 

 range, i.e., to n, where 30-w represents the lowest pressure in inches. 



To show this in a simple way, I give in Tables IX. and X. the mean results obtained 

 by multiplying the observed falls by (18,000 -f- range). The constant was chosen so 

 as to avoid decimals. The actual fall in inches is of course obtainable by multiplying 

 the figures in the table by (range -f- 18,000). 



TABLE IX. Fall at Lowest Point X (18,000 -4- range). 



TABLE X. Same quantity as in Table IX. 



VOL. CXCJ. A. 



3 N 



