History
In 1800 the English astronomer William Herschel held a mercury thermometer in the spectrum produced by a glass prism to measure the heat content of different coloured light. He found that the thermometer registered an increase in temperature even when held beyond the red end of the spectrum, where there was no visible light. This invisible light form has become known as infrared light.
Infrared light makes up part of the sun’s invisible spectrum of light waves that are essential for all living creatures. Infrared light waves penetrate human tissue and causes an activation of thermal energy creating a sensation of heat. Far infrared rays, the most beneficial type, are completely safe and are used by hospitals to warm newborn infants.
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