360 Proceedings of the Royal Society of Victoria. 



column, the difference in altitude of the two points is found. 

 But this Table is correct only where the average temperature of 

 the air is 32' F. For any higher temperature the result must be 

 increased in the subjoined ratio. 



Table II. 



Temperature. Multiplier. 



32° 

 37° 



41" 

 46° 

 50° 

 54° 

 59° 

 63° 



1.00 

 1.01 

 1.02 

 1.03 

 1.04 

 1.05 

 1.06 

 1.07 



Temperature. Multiplier. 



68° 

 72° 

 77° 

 81° 

 86° 

 90° 

 95° 

 100° 



1.08 

 1.09 

 1.10 

 1.11 

 1.12 

 1.13 

 1.14 

 1.15 



Reading at lower station 

 Instrumental correction 



Example. 



28.61 

 .04 



28.65 

 Corresponding number from Table I. 

 Reading at upper station - - 26.78 



Instrumental correction - - .06 



26.84 



Corresponding number from Table I. 



5131+^^91 = 5176 



3433 + 3-^97 = 3472 



1704 



Difference 



Average temperature of intermediate air 60° F. 

 Multiplier from Table 11. 1.062. 1704 x 1.062 = 1809.6 feet. 



The same example worked out from Guyot's Tables, which are 

 much more voluminous than the preceding, gave 1810.3 as the 

 result, or about 8 inches more. It is not too much to state that 

 no aneroid in existence could be depended upon to give this 

 heiglit by a single pair of observations within several feet of the 

 truth. Thus this discrepancy is seen to be absolutely unim- 

 portant. 



