Upon a change in the temperature of thermal bulb 1, filled with gas and immersed in the medium whose temperature is to be measured, the pressure changes in capillary tube 2 and in helical tubular spring 3, connected to tube 2. One end of the tubular spring is fixed and the other end, which moves when the spring is wound up or unwound by the change of pressure inside it, turns shaft A. Spring 3 is linked to shaft A through yoke 4. Shaft A is linked through lever 5, tie-rod 6 and lever 7 to shaft B. Rigidly mounted on shaft B is hand 8 or a pen which registers the temperature being measured.
$4064$EHP,M$