TABLE 140. 

 PRESSURE OF AQUEOUS VAPOR IN THE ATMOSPHERE. 



155 



This table gives the vapor pressure corresponding to various values of the difference t ^ between the readings of 

 dry and wet bulb thermometers and the temperature ^ of the wet bulb thermometer. The differences t t^ are 



E:n by two-degree steps in the top line, and t^ by degrees in the first column. Temperatures in Centigrade 

 rees and Regnault's vapor pressures in millimetres of mercury are used throughout the table. The table was 

 ulated for barometric pressure B equal to 76 centimetres, and a correction is given for each centimetre at the 

 top of the columns.* 



* The table was calculated from the formula /=/ t 0.00066 J3 (t ^) (1+0.00115^) (Ferrel, Annual Report 

 U. S. Chief Signal Officer, 1886, App. 24). 



t When B is less than 76 the correction is to be added, and when B is greater than 76 it is to be subtracted. 



SMITHSONIAN TABLES. 



