History of Infrared
Infrared radiation was discovered in 1800 by Sir William Herschel while he was measuring the temperature of the various colors of the visible spectrum separated by a prism. Herschel observed that the temperature of his thermometer increased as he moved it from the blue to the red. When he accidentally placed his thermometer beyond the red region of the visible spectrum, he noted a further increase in temperature. Herschel called this invisible light “infrared”, meaning below the red.