439 



air, which I here subjoin, enabled me, by means of this ex- 

 pression, to calculate 19 additional values oim. 



Series 2. 



**3. Lastly, if in the formula/^' and/' be known, so also 



is m, for it is obviously equal to 



r-f 



30 



But in 



the case of air saturated with humidity, by being passed 

 through water, its temperature is its dew-point; so that this 

 latter is easily and certainly known. Hence, if the tempera- 

 ture of such air be raised, and a wet and dry thermometer 

 be observed in it, we have t, f and t" ; and can therefore, by 

 the expression just given, calculate the value of m. The 

 following table includes 24 distinct observations, from which 

 the values of the coefficient given in the last column have 

 been thus deduced : 



