439 



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

 pression, to calculate 19 additional values of m. 



Series 2. 



No. 



t 



t' 



t — t' 



P 



m 



1 



51 



33-5 



17-5 



30-55 



•0122 



2 



53 



34-5 



18-5 



30-35 



•0116 



3 



52 



34 



18 



30-21 



•0118 



4 



51 



33 



18 



30-05 



•0115 



5 



52 



33-4 



18-6 



29-75 



•0108 



6 



53 



34-3 



18-7 



29-50 



•0118 



7 



56-5 



358 



20-7 



29-70 



•0112 



8 



58 



37 



21 



29-72 



•0110 



9 



58-2 



37 



21-2 



29-77 



•0113 



10 



58 



37 



21 



30-03 



•0114 



11 



58 



37 



21 



30-15 



•0113 



12 



59 



37-5 



21-5 



30-25 



•0112 



13 



59 



38 



21 



30-26 



•0117 



14 



61 



38-7 



223 



30-21 



0113 



15 



58-3 



37-7 



20-6 



30-35 



•0117 



16 



58 



37-5 



20-5 



30-45 



•0117 



17 



56-3 



36-5 



19-8 



30-30 



•0117 



18 



57-5 



37 



20-5 



30-20 



•0116 



19 



57-5 



37 



20-5 



30-15 

 Mean. : 



•0116 



= -01150 



"3. Lastly, if in the formula f" and/' be known, so also 



is m, for it is obviously equal to 



/'-/' 



30 



But in 



t-t' p-f 



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, t' 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 : 



