Expansion Apparatus Gunter

Comprising two cast end pieces, joined by three nickel-plated rods, caring two sliding V-supports for a glass jacket with inlet and outlet tubes.
One end-piece fitted with spherometer reading to 0.005 mm, and the other with contact screw.
The glass jacket enclosed both a brass and a copper rod each 500 x 7 mm length x diameter, fitted through corks , a half turn of the jacket changing rod in contact with the spherometer.
A thermometer can be attached to be either of the rods by rubber bands. Brass terminals are fitted to the apparatus so that an electrical circuit can be made through either rods, to indicate the moment of contact of centre tube and spherometer.
Supplied with 3 metal rods one each of copper, brass and iron.