HEAT OF EVAPORATION OF WATER. 319 



TABLE XVI. 
Lfrom “ preliminary ” 
Temperature. observations L from formula Gy. 
(Table IX.) 
| ° f : 
| 25:0 581-9 581°70 
| 40-0 572°4 572°69 
49°8 566°5 566°80 



I have given in Section II. my reasons for rejecting ReGNAULT’s experiments at 
low temperatures, where he determined the temperature in the calorimeter from the 
pressure of the vapour in the condenser. The objections there brought forward, 
however, lost all force as regards these experiments above 63° in which the methods 
of observation and experiment were altered. 
Column III. of the following table gives the results of all RecNAvLt’s experiments 
above 63° and below 100°... (R.), Column IV. gives the values resulting from 
ReGNAULTS own formula 606°5 + °305¢....(R), Column V. contains those given 
by WINKELMANN’S formula*..(W), which includes RecGnautt’s expression for 
the capacity for heat of water, and Column VI. the numbers obtained by assuming’ 
the validity of formula G, (supra), from which we deduce 
Total Heat = 596°73 + 39900... . (Gy). 
Column VII. gives the difference between (R.) and (R), in Column VIII. are given 
the differences between (R,) and (W), and Column IX. shows the differences between 
(R.) and (G,). 
* L = 589°5 — 0:2972¢ — 000321472? + 0:00000814 70. 
