|Continental Holiday. The American Travel Guide to Europe. New York, 1961.
According to its Wikipedia entry:
"The Atmos Clock is a timepiece of near-perpetual movement needing no human intervention and almost no energy. Invented by Swiss engineer Jean-Léon Reutter in 1928 in Neuchâtel, the Atmos clock has been the Swiss government’s official gift for important guests since 1950. Patented in 1928, the first version – known today as the Atmos 1 – was marketed by La Compagnie Générale de Radiologie (CGR) in 1930."
On another website:
"Since 1928, the mechanism of the Atmos clock fascinates by its exceptional mode of operation with no battery, no electric current and no winding. It lives on air by means of an ingenious principle: a hermetically sealed capsule containing a mixture of gases that expands when the temperature rises and contracts when it drops. Connected to the mainspring of the clock, the capsule acts like a concertina or a pair of bellows, thereby constantly winding the mechanism. It is so sensitive that a one-degree temperature difference is enough to power it for 48 hours. Its balance oscillates just twice a minute rather than the average 300 times of a classic wristwatch, which consumes 250 times more energy than an Atmos clock. The 190 parts that compose this clever construction are precision-assembled within the Manufacture."