RICHARDS AND MATHEWS. 



HEAT OF EVAPORATION. 



533 



Weight of condensing coil and condensed liquid 



Weight of condensing coil alone 



Weight of vapor condensed (licjuid vaporized) 



Total heat effect per gram = — — ' ,,^ -,'.'" 



10.014 



Heat given out by cooling 1 gram from 100.0° 



to 21.42° 

 Uncorrected heat of vaporization of one gram of 



water 



speed more clearly manifest. The first five experiments made early in 

 December, 1907, were all consecutive; but that numbered 6 was exe- 

 cuted long after the others (in January, 1908), after the vacuum jacket 

 had been used for higher boiling liquids, and had unfortunately cracked. 

 Except for its somewhat larger warming correction, no essential differ- 

 ence could be detected between its results and that of the preceding 

 experiment, carried out at the same rate. The last experiment was 

 conducted under a pressure of 757 millimeters of mercury, the others 

 were practically at normal pressure of 760 millimeters. 

 The table explains itself. 



Heat of Evaporation of Water. 

 Series 1, with Vaporizer I. 



