Pneumatic clock from 1940
Watchismo's got the news on Puja's 1940 Thermo-Pneumatic Clock -- a time-keeping apparatus like no other:1940 Puja Thermo-Pneumatic Clock
"At the lower left, shielded by a translucent housing, is a carbon rod resistance that heats the colored alcohol in the glass vessel just above it. This causes some of the alcohol to vaporize, the pressure pushing the liquid up the connecting pipe to the vessel at top right. As the latter gets heavier the wheel bearing the four vessels experiences a torque that rewinds a remontoire spring driving a conventional gear train and escapement. This clock has a pendulum-controlled escapement, but models with balance wheel escapements also existed."
Where not otherwise specified, this work is licensed under a Creative Commons License permitting non-commercial sharing with attribution. Boing Boing is a trademark of Happy Mutants LLC in the United States and other countries.