50 PSYCHROMETRICAL TABLES. 



mometers, which are greater by one tenth than those indicated in the tables, is given 

 in the horizontal column at the bottom of the page. It is constant and always sub 

 tractive. 



Examples of Calculation. 



Difference of thermometers, or t t 1 = 0.8. 



Temperature of the wet-bulb thermometer, t' = 11.0. 

 We find, page 18, for t /', fifth double column ; and for ', first column, 



The force of vapor in the air = 9 mra> .31. 



Relative humidity, = 90. 



Difference of thermometers, or t //, = 7.2. 

 Wet-bulb thermometer, or //, 17.9. 



We find, page 24, for * *',= 7.2, and t 1 = 17.0, force of vapor 10 mra -.02. 

 Additive correction for fraction 0.9, or 9 X 0.09 =0 .81. 



Force of vapor in the air = 10 .83. 

 Relative humidity, 46 



Difference of thermometers, t t' = 6. 5. 

 Wet-bulb thermometer, /' = 23.6. 



We find, page 23, for t' = 23.0, and t t', or difference, = 6.4, force of vapoi 

 jgmm 94 . a ppiyi n g immediately the correction found at the bottom of the page for one 

 tenth more difference, or 6.4 + 0.1 = 6.5, we have, 



Force of vapor = 16 mm .94 0.06, or 16 mm -.88. 



Additive correction for fraction 0.6 of the wet-bulb, 6 X 0.13 = .78. 



Force of vapor in the air = 17 .(56. 

 Relative humidity, 56. 



The wet-bulb thermometer covered with ice. 



Difference of thermometers, t /.'= 2.8. 



Wet-bulb thermometer (ice), t'= 8. 5. 



Page 17 gives for *' = 2.8, and t 1 = 8.0, force of vapor = l mm \0. 

 Subtractive correction for fraction 0.5 of wet-bulb, 5 X 0.019 = .1. 



Force of vapor in the air = .9. 

 Relative humidity, 30. 



B 14 



