Heating Effects of a Current

   This piece of apparatus is at Case Western Reserve University in Cleveland, Ohio, and was made by Max Kohl of Chemnitz, Germany.

   I cannot find it in either the 1900 Kohl catalogue or the one from about 1928, but hypothesize that it was used to demonstrate the heating effects of the electric current that passed through the conductor in the sealed glass bulb. The air in the bulb expanded, thus pushing the oil in the manometer down on the left-hand side.