in the Condensation of the Vapour of Water. 65 
sulted from the condensation of this vapour, did not prevent the 
vapour from continuing to flow through these passages. 
Thisvapour came from a long-necked matrass containing distil- 
led water, which was put on a portable stove placed in a chim- 
ney at some distance from the calorimeter; and in order to stop 
all direct communication of heat between the stove and the ca- 
lorimeter, the former was masked by plates, and the tube which 
conducted the vapour to the calorimeter was well covered with 
flannel. 
The cold water which filled the calorimeter was of a lower 
temperature than that of the chamber by 6° of Fahrenheit and 
‘when the thermometer of the calorimeter announced an aug- 
mentation of temperature by 12° of Fahrenheit, an end was put 
to the experiment. 
The water produced by the condensation of the vapour in the 
serpentine was carefully weighed ; and from its quantity, as well 
as from the heat communicated to the calorimeter, the heat de- 
veloped by the vapour in its condensation was determined. 
As a small part of the heat communicated to the calorimeter 
proceeded from the cooling of the water condensed in the ser- 
pentine, after the vapour had been changed into water, an ac- 
count was kept of this heat. It was supposed that the water at 
the moment of condensation was at the temperature of 212° F. 
being that of boiling water; and it was determined by calculation, 
what part of the heat communicated to the calorimeter must 
have been owing to this boiling water. 
In making this calculation, no account was taken of the dif- 
ference in the capacity of water for heat, which depends on its 
temperature : this is but imperfectly known; aud besides, the cor- 
rection which would have been the result, could not but have 
been very small. 
The following are the details and results of two experiments 
made on the 2\st of January 1812. 
a —& | xtate of the Calorimeter (equal| ¢ 3 
. ° q 
= g in capacity for Heat to2781) 5 = Result. 
2 re Grammes of Water.) ea Loy 
& 7) n =o — & o an 
i P| =e pa yee Sam 2 ce 
v = Pairs} 3 ej n oak Be Get rar jae 
[=> id 45 ez ae & Se be 
al o “hee om pe SS Su | 
f we ov oC [oP] uw - baat ib cS oconzo 
onl Ws ead eS |e S¢ orgs 
te 3 see/5, Oia, | ORS eo eS ol (o 
e =< |S22)/e66] 82 mo es Ae oe 
a) (3) NE o & ey wert oy hehe Ts 
v= ay pat Spl BB Sia a5 eae le Se 
FI oO =—25 > wv es 
= e sien) <2| Eqs 5 Som |ate 
~ oe —_— Ro, . ~ - ae} 
Zz es ra = a Gg Shih 
grammes. lbs. 
| 61° | $50 674 124 | 2961 10293 
2 624°! 574° 674 104 2404. 1052°3 
Mean Result 7040'8 
Vol. 43. Nov489, Jan, 1814, Dy By 
