Medical thermometer measurable scale on the thermoscope and wrote of it in 1625, though he possibly invented one as early as 1612. His models were bulky, impractical and took a fair amount of time to take an accurate oral reading of the patient's temperature. Two individuals switched from water to alcohol in the thermometer. Fahrenheit also created the temperature scale which is named after him, having recorded the system in 1724. The scale is still only mainly used for everyday applications in the United States, its territories and associated states (all served by the U.S. National Weather Service) as well as the
Thermodynamic temperature as SPRTs, PRTs or Platinum RTDs) and monochromatic radiation thermometers. For some types of thermometer the relationship between the property observed (e.g., length of a mercury column) and temperature, is close to linear, so for most purposes a linear scale is sufficient, without point-by-point calibration. For others a calibration curve or equation is required. The mercury thermometer, invented before the thermodynamic temperature was understood, originally "defined" the temperature scale; its linearity made readings correlate well with true temperature, i.e. the "mercury" temperature scale was a close fit to the true scale. The thermodynamic temperature is a measure of the average