DR. J. JOLY ON THE SPECIFIC HEATS 
902 
photograph) shows the details of construction in so far as there is departure from 
the general arrangements of the differential steam calorimeter, as described in the 
‘ Proc. Roy. Soc.,’ vol. 47, p. 218. 
The lids of both the inner and outer chamber are shown removed at the end 
nearest the spectator, so that the active sphere containing the gas can be seen 
lianging in its place. From it dejDends the light platinum catch-water. The 
calorimeter can be opened in a similar manner at the remote end, to facilitate 
removing the idle sphere and drying the walls. All is made of very light brass, but 
both the inner and outer drums are flanged by stiff L-pieces on the ends, which are 
ground true and smooth, so that the lids or covers (which are of thin brass, “ dished” 
