Medical thermometer (1836–1925) designed a medical thermometer that was much more portable, measuring only six inches long and taking only five minutes to record a patient's temperature. In 1868, German physician, pioneer psychiatrist, and medical professor Carl Reinhold August Wunderlich published his studies that consisted of over one million readings from twenty-five thousand patients' temperatures, taken in the underarm. With his findings, he was able to conclude a healthy human's temperature fell within the range of 36.3 to 37.5 °C (97.34 to 99.5 °F). Dr. Theodor H. Benzinger (13 April 1905 - 26 Oct 1999) invented the ear thermometer in 1964. Born
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