122 EXPERIMENTAL GENERAL SCIENCE 



liquid, such as water or alcohol were used, the tube would have 

 to be very much longer in order to accommodate an equal 



FIG. 40. An aneroid barometer. (Tower, Smith and Turton.) 



FIG. 41. The barograph. 



weight of the liquid. The aneroid barometer is a more portable 

 instrument for measuring pressure. It consists of a thin- wall ed , 

 air-tight flat metal box, with a thin corrugated top, from which 



