Huygens barometer? Circa 1672 the Huygens barometer was invented by the Dutch physicist Christiaan Huygens (1629-1695) The Huygens tube has a U-shape and contains mercury and an oil-like fluid The contact surface mercury/liquid is enlarged, so that a small difference in the mercury level causes a major change in the oil-like liquid level That’s the reason why the scale of the Huygens barometer is 5 times bigger compared to the Torricelli barometer and the movements in the tube are much more visible ad can be seen at the barometers The Huygens barometer is also called contra barometer because of the opposite direction of rising and falling of the liquid as compared to the Torricelli barometer If the liquid rises in the Torricelli tube, then the scale indicates more stable weather While with the Huygens tube the scale indicates more turbulent weather The Huygens tubes were used in French, Dutch and Scandinavian barometers Often also in combination with a Torricelli tube, acting as a controller!