General
Toricelli mercury barometers measure continuously the changes in air pressure. To estimate forecasts, one has to set the index on the glass tube to the actual mercury level. The tendency of the atmospheric air pressure and the amount of change make a reliable forecast possible..
Evangilista Toricelli was an Italian Scientist in the seventeenth century (1608-1647). He was looking for a way to prove that the air had a certain weight.
He took a glass tube, enclosed at one side, and filled that tube completely with mercury. Now all air was out of the tube. He locked the tube on the open side with his thumb and turned the tube upside down in a reservoir, filled with mercury. Now he released his thumb and he noticed that a certain amount of mercury was kept in the tube. The air pressure on the surface of the mercury in the reservoir pushed the mercury column up and down in the tube.
He noted an average height of 76 centimeters after repeating the experiment. One other observation was, when the column mercury went down, the weather went bad, and when the mercury climbed up in the tube, the weather changed to fair. This was the birth of the first actual and reliable weather instrument.
Toricelli Mercury barometer
Mercury barometer according Evangilista Toricelli combined with an alcohol thermometer (Blue color).
- Total weight of the weather station: 1.800 g
- Background in parchment, black imprinted
- Available as shown on the picture
- Barometer scale shows millimeter and hectoPascal
- Thermometer scale in Centigrade and Fahrenheit
- Available with Dutch, German, French or English.
- German, French & English version, a height-adjustment-scale is added
- Frame: 1020 x 180 mm