532 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



Heat of Vaporization of Water. 

 Determination No. 2. 



Time when fteading 

 was taken 



1.21 

 1.22 

 1.23 

 1.24 

 1.25 

 1.26 

 1.27 

 1.28 

 1.29 



Observed Thermom. Reading 

 in Water in Calorimeter 

 (uncorrected). 



0.090° 

 0.098° 

 0.107° 

 0.116° 

 0.125° 

 0.134° 

 0.143° 

 0.152° 

 0.161° 



1.29 Vapor turned into coil. 



1.34 Electric current stopped. 



1.35 5.100° 



1.36 5.117° 



1.37 5.128° 



1.38 5.138° 



1.39 5.147° 30 



1.40 5.155° 



1.41 5.164° 



Average, 



Increase in Temper- 

 ature per Minute. 



0.008° 

 0.009° 

 0.009° 

 0.009° 

 0.009° 

 0.009° 

 0.009° 

 0.009° 

 0.009"" 



Reading of 

 Thermometer. 



Final temperature 

 Initial temperature 

 Total rise in temperature 



5.147° 

 0.161° 



Correction to reduce 

 Reading to true 

 Temperature. 



+ 18.787 

 + 18.760 



0.017° 

 0.009° 

 0.010° 

 0.009° 

 0.008° 

 0.009° 



Corrected Temperature 

 Hydrogen Scale. 



23.934' 

 18.921° 



= 5.013° 



= 0.086' 



Rise due to radiation and conduction (2.5 X 0.009° + 



7.5 X 0.0085) 

 Rise in temperature due solely to condensation of vapor 

 and cooling of resulting liquid to temperature of 

 calorimeter = 4.927° 



Water equivalent of calorimeter and fittings 53.4 grams 



" water in calorimeter 1252.9 



" " \ the liquid condensed 5.26 



Total water equivalent 1311.56 grams 



^" Point at which rise of temperature due to condensation of vapor ceased. 

 Further increase of temperature, since the rise did not exceed 0.0085° per 

 minute, was due to radiation from vaporizer. 



