Irish Famine (1740–41) affect economies, energy sources, and politics. Although no barometric or temperature readings for Ireland survive from the Great Frost, a scattered few records survive from Englishmen who made personal readings. The mercury thermometer was invented 25 years earlier by the German pioneer Daniel Gabriel Fahrenheit. Indoor values during January 1740 were as low as . The one outdoor reading that has survived was stated as "thirty-two degrees of frost." This did not include the effects of the wind chill factor, which would have been severe. This kind of weather was "quite outside the Irish experience," notes David Dickson, author of
Reversing thermometer They are usually read to 0.01°C, and after the proper corrections have been applied, their readings are considered reliable to 0.02°C. Reversing thermometer Unlike most conventional mercury thermometers, a reversing thermometer is able to record a given temperature to be viewed at a later time. If the thermometer is flipped upside down, the current temperature will be shown until it is turned upright again. This was the primary device used by oceanographers to determine water temperatures below the surface of the ocean from around 1900 to 1970. It consists of a conventional bulb connected to a capillary in which a