Linear Expansion Apparatus, Gunther

Comprising two cast metal end pieces joined together by three nickel plated rods and carrying two sliding V-supports for a glass jacket with inlet and outlet tubes. One end piece fitted with spherometer reading 0.01mm, and other with contact screw. The glass jacket encloses both a brass and a copper rod each of about 50cm length, fitted through corks, a half turn of the jacket changing rod in contact with the spherometer. A thermometer can be attached to either of the rods by rubber bands. A binding post is fitted to each end piece for connecting an electric bell or galvanometer to indicate make/break of contacts.