*go 



^'^"^^jilatiation of the Theoijofthi 



[July, 



^^lrtfi^Wte})ferfttitt6'kJ^n^9-8° F. H^. we:^ubstituted the ratio of 

 ^S'te^^yfAlviH^^h BV SAussure and Watt/^ the^iteBMaeriiture would 

 *MV^^Wtt^'b^tJ97'4^^^V ^ iriJ0iJz3 3"/ al . .; .>r 



^?;' fiitf^VW^'th^ fblldt^ihg table wittthe degteeof teraperatiire 

 indicated by a thermometer in contact with saturated air sup- 

 porting' a pressure of 30 inches, we have but to add to the 

 observed temperature the corresponding equation, given in 

 .'degrees and tenths, and the sum will indicate the temperature at 

 which the density of diy air under the same pressure will equal 

 that of the saturated air. When the pressure differs from 30 

 ^TOcjh^efei. multiply the equation by 30 inches, and divide the pro- 

 '. duct' by the observed pressure. The error iii tZe/ec^ resulting 

 '*fi*oiW'^his Approximative method will not exceed one-third of a 

 d'e^ee' in any case within the limits of barometrical observa- 



tions. 



We must now propose a case of 2i\v partially saturated with 

 aqueous vapour, the pressure being as before 30 inches, the 

 temperature 90°, and the dew-point of the vapour 70°. 



Calculation. 



'at 32-00^ Volume 480-00 Density 480-000 



Dryair^ 90-00 538-00 428-253 



95*23 543-23 424-131 



Lir< 



Moist air at 90°. Dew-point 70°. (Force of the vapour 

 0-77 in.) Density per formula 424-131 (or 428*253 wzmws a of 



^'^ of 428-253). 



The density of the moist air is consequently equivalent to that 

 of dry air of the tiemperature of 95*23°. 



With some trifling sacrifice to extreme accuracy, the preceding 

 table will also serve to determine the equations for air not con- 

 taining its maximum quantity of humidity. Enter the table 

 with the observed dew-point (70°), instead of the degree of 

 temperature indicated by the detached thermometer (90°), and 



