177 



Tables 128 and 129 



RELATIVE DENSITY OF MOIST AIR FOR DIFFERENT PRESSURES 

 AND HUMIDITIES 



TABLE 128. — Values of z-^r, from h = 1 to h = 9, for the Computation of Different Values 

 760 

 of the Ratio of Actual to Normal Barometric Pressure 



This gives the density of moist air at pressure h in terms of the same air at normal atmosphere pres- 

 sure. When air contains moisture, as is usually the case with the atmosphere, we have the 

 following equation for pressure term: h = B — 0.378?, where e is the vapor pressure, and B the 

 corrected barometric pressure. When the necessary psychrometric observations are made the value 

 of e may be taken from Table 212 and then o.3;8e from Table 130, or the dew point may be found 

 and the value of 0.378* taken from Table 130. 



Examples of Use of the Table. 



To find the value of — when h = 754.3 

 760 



h = 700 gives .92105 



50 " .065789 



4 ' .005263 



.3 " .000395 



754-3 



.9., 2407 



To find the value of — when h — 5.73 

 760 



h = 5 gives .0065789 

 .7 " .0009210 

 .03 " .0000395 



5-73 



.0075394 



TABLE 129. — Values of the logarithms of ^^ for values ol h between 80 and 800 



760 



Smithsonian Tables. 



