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Thanks to http://www.thermology.com/history.htm for this awesome history lesson on Thermology -
The ancient Egyptians
moved their
hands across the surface of the body to scan and monitor changes in
temperature.
The fingers acted as sensors and the brain interpreted the relevant
changes.
They could effectively evaluate the rise in temperature over a period
of
time. It could be isolated to a specific area, or determined that there
was a general increase over the entire body.
- The Greek Physician,
Hippocrates,
wrote in 400 B.C. "In whatever part of the body excess of heat or cold
is felt, the disease is there to be discovered." The ancient Greeks
immersed
the body in wet mud. The area that dried more quickly indicated a
warmer
region, and was considered the diseased tissue. (ref.
Thermography & Personal Injury Litigation. Wiley Law Publications,
Samuel Hodge Jr., 1987. pg. 71)
- Heat is a property of the body.
Temperature refers to a certain standard of reference. The use of hands
to measure heat emanating from the body remained well into the
sixteenth
and seventeenth centuries. It wasn't until Galileo, who made a
thermoscope
from a glass tube, that some form of temperature sensing device was
developed,
but it did not have a scale. It was the work of Fahrenheit, who fixed a
lower point by using salt with ice water and ranged to boiling water at
212 degrees. Celsius, in 1742, created a decimal scale, using "zero" as
the boiling point of water and 100 as the freezing point. His scale was
reversed by the Swedish botanist Linnaeus. Increasing heat was
indicated
by higher temperatures. Prof. Carl Wunderlich of Leipzig in 1868
advanced
the use of thermometry in medicine with the first set of temperature
charts
on individual patients with a wide range of diseases. He proposed the
design
of the present day clinical thermometer, which is now slowly being
replaced
by disposable sterile thermocouples and radiometers for middle ear
temperature.
(ref. Prof. E.F.J. Ring, Royal National Hospital for Rheumatic
Diseases,
Bath, England. University of Glamorgan - Inaugural Lecture Jan. 28th,
1997)
The use of Liquid_crystals
became another
method of displaying skin temperature. Cholesteric esters can have the
property of changing color with temperature, and this was established
by
Lehmann in 1877. The practical application involved the use of
elaborate
panels that encapsulated the crystals and were applied to the surface
of
the skin, but due to a large area of contact, they affected the
temperature
of the skin.
All the above methods for
measuring human
body temperature are contact methods. The major advances of the last 30
years have been with infrared thermal imaging.The surface of the human
body is a highly efficient radiator and it is possible to detect the
infrared
emission from the skin, and create a thermal map of temperature
distribution
by remote sensing. (ref. Prof. E.F.J. Ring,
Royal National
Hospital for Rheumatic Diseases, Bath, England. University of Glamorgan
- Inaugural Lecture Jan. 28th, 1997) The astronomer, Sir William_Herschel,
in Bath, England, discovered the existence of infrared radiation by
trying
to measure the heat of the separate colors of the rainbow spectrum cast
on a table in a darkened room. He found the highest temperature to fall
beyond the red end, which he reported to the Royal Society as Dark Heat
in 1800. His son, Sir John Herschel, who was more interested in
photography,
managed to record the heating rays on the infra red side of red by
creating
an evaporograph image using carbon suspension in alcohol. He termed
this
image a thermogram. The foundation was laid for the advances that would
come over a century later with the sophisticated thermal imaging
devices that are used in military, industrial and medical applications. Heat_death_of_the_universe
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