DETERMINATION OF THE SPECIFIC HEAT OF WATER. 441 




TasiE VIII. 
| | 
| Material. | Weight. Specific heat. | Water-equivalent. 
IZOrCe lara ye | 23°32 196 4°59 
Plabinoi dey Fis, ees ee 5°76 102 D9 
Glasses Se ge oo eet or 5°58 “190 1-06 
prass ge VAs CATS 42°55 090 3°82 
Copper terminals. . . 2°04 | 092 ‘19 
| otal ae 10-25 




This refers to a temperature of about 60°, and agrees sufficiently well with the 
equivalent 9°96 which was directly determined, if we remember that the specific 
heats of porcelain and platinoid are, for the reasons given, too high, and that the 
values for the specific heat of brass and glass were assumed to be those usually 
given. 
We must add 0°34 to the water-equivalent belonging to a silver disc covered with 
gold foil, which was kept floating on the surface of the water in order to prevent 
evaporation as far as possible, 
As regards the thermometer, we calculated the specific heat from the data inscribed 
on it by the maker, according to which the weights were as follows :— 
IWerehtioftmercugvie.)0) (lal et nO OReTAIMNSs 
Weichtiofjclassi bulbs: 1-oss5isnie 62. ol Sorerams: 
Wierchiioteclasspnistemun sien aey as te ee 2OnOe at 
Taking the specific heat of mercury to be 0°033, and that of glass 0°19, we calculate 
that the water-equivalent up to the point marked 12° was 2°05. An experiment made 
to determine directly the equivalent of the thermometer, showed that we could trust 
the figures given by the maker, the value found being identical with that calculated 
from his data. We may add 2:05 permanently to the water-equivalents, and in the 
separate experiments correct for the additional length of the stem immersed, which 
was slightly different on different occasions. The correction is determined by the fact 
that the water-equivalent corresponding to a length of 1° of the stem is 0°34. We 
may take, therefore, as the equivalents which were the same in all experiments :— 

@alonmetervic tic jan ie eae wee mn cite timate le pil 
Heatme coil, frameand Shirteray ee) oe 9209 
StveridisGs ico. S~ taeseere ee pe pe RE hal afk VOLE 
ierinometer as tay, as; market: Wee ne 2205 
Parts surrounding calorimeter. . . .. . . 0°33 
27°02 
ise) 
i 
MDCCCXCY.—A. 
