234 Mr Anderson’s Corrections for the Effects of Humidity 
ingly have recourse, in the first place, for the illustration of the 
formula, to the observations which Sir George Shuckburgh 
made, to determine the height of Mount Saleve, as they are re- 
corded in the 67th volume of the Philosophical Transactions. 
These observations, it may be proper to state, were made for 
the express purpose of verifying the accuracy of De Luc’s rules 
for measuring heights by the barometer. 
Bar. Att. Therm. Det. Therm. 
Observations at the lower station, 28.395 72°.l 73.°9 
Observations at the upper station, 25,712 78° 65° 
The height of the barometer at the upper station was ob- 
served in a tent, in which, it is stated, that a detached thermo- 
meter stood at 7£°. 
Here no element is wanting for the determination of the 
height, except the humidity of the atmosphere at the time of 
the observations ; and the only way it can be supplied, is to 
assume, that the quantity of moisture existing in the air was 
such as it is generally found to be, when the atmosphere is in a 
mean state of humidity. The temperature being pretty high, 
it may be supposed that the point of deposition was 10° below 
the temperature of the air, or at 63°. 9. This supposition would 
give, by Dalton’s Table, the tension of vapour, corrected for 
the difference of temperature between the point of deposition 
and the temperature of the air, *607. The elastic force of the 
atmospheric vapour, at the upper station, determined in the 
same way, would be ’4 52. The several coefficients computed 
separately, are as follows : 
1 . Correction for the temperature of the air. 
1 + .002086 f t+£_ 32°) = 1 + -002086 — 32°) 
= 1 + -002086 x 37.45 = 1-07811. 
2. Correction for the difference of temperatures of the mer- 
curial columns, at the two stations. 
25-712 (1 + -000103. T — T') =25-712 (l + .000103 • 72-1—78°) 
= 25.712. (1 + -000103 x — 5 9) = 25-712 x 99939 = 25 696. 
