Leeches, jars and a bell: how they learned the exact weather forecast in the 19th century

Today there is no particular problem with the forecast of storms, storms and other climatic deviations: the whole planet is covered by a network of meteorological stations that collect weather information daily. But back in the century before last, sailors and shipowners were in dire need of some kind of device that could predict the weather changes for the worse. Leading engineers and scientists struggled to resolve this issue, and it was found. The device was called the "Storm Predictor" with leeches, and there really were leeches that coped well with the role of predictors.

A very original device, authored by physician George Merriweather, was presented at the 1851 World's Fair in London. The main elements of the storm predictor were 12 small (a little more than half a liter) glass bottles of water with leeches. Before the stormy weather approached, the leeches were anxious, feeling the increased electromagnetic voltage in the air, and tried to get out. Due to the movement of leeches, the threads starting from the bottles began to twitch, which caused the ringing of the bells located above. By the intensity of the ringing, the strength of the impending storm was determined. Dr. Merriweather himself called his invention "Atmospheric electromagnetic telegraph, driven by animal instinct."

Leeches turned out to be excellent predictors, and the effectiveness of this method has been proven by scientific experiments. But, despite the high reliability of forecasts and ease of manufacture, this unique device has not found wide application. There were several orders for home versions of the device, but the sailors found it too cumbersome and preferred another option - the Fitzroy storm class. This competitor of Dr. Merriweather's leeches consisted of a flask filled with an alcoholic solution of camphor, ammonia and potassium nitrate. By the way, most modern experiments do not confirm the effectiveness of this storm predictor, which for some reason was considered more effective than the predictor of leech storms, but the story can no longer be changed.

Currently, two copies of Dr. Merriweather’s instrument, capable of predicting the approach of the storm, are in museums in the United Kingdom: the Whitby Museum and the Devon Meteorology Museum.