Page:Popular Science Monthly Volume 17.djvu/33

Rh The object of the funnel-shaped opening, with a small slit facing A, is to cut off all heat which is not wanted.

The tasimeter can also be used as a delicate hygrometer; by inserting



a piece of any substance which is capable of changing in volume as the effect of a change in moisture in the air, the pressure on the carbon will be varied accordingly and indicated by the galvanometer.



The great sensitiveness of this instrument makes it seem probable that it will be used for many purposes not at present thought of. Special modifications for particular purposes are always possible. Fig.