THE CARBON BUTTON. 



23 



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 insert- 



ing 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. 



*SS 



Fig. 9. Perspective view op Micro-tasimeter. 



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. 



