from
The Collaborative International Dictionary of English v.0.48
Thermometer \Ther*mom"e*ter\ (th[~e]r*m[o^]m"[-e]*t[~e]r), n.
[Thermo- + -meter: cf. F. thermom[`e]tre. See {Thermal}.]
(Physics)
An instrument for measuring temperature, founded on the
principle that changes of temperature in bodies are
accompanied by proportional changes in their volumes or
dimensions.
[1913 Webster]
Note: The thermometer usually consists of a glass tube of
capillary bore, terminating in a bulb, and containing
mercury or alcohol, which expanding or contracting
according to the temperature to which it is exposed,
indicates the degree of heat or cold by the amount of
space occupied, as shown by the position of the top of
the liquid column on a graduated scale. See
{Centigrade}, {Fahrenheit}, and {R['e]aumur}.
[1913 Webster] To reduce degrees Fahrenheit to degrees
Centigrade, subtract 32[deg] and multiply by 5/9; to
reduce degrees Centigrade to degrees Fahrenheit,
multiply by 9/5 and add 32[deg].
[1913 Webster]
{Air thermometer}, {Balance thermometer}, etc. See under
{Air}, {Balance}, etc.
{Metallic thermometer}, a form of thermometer indicating
changes of temperature by the expansion or contraction of
rods or strips of metal.
{Register thermometer}, or {Self-registering thermometer}, a
thermometer that registers the maximum and minimum of
temperature occurring in the interval of time between two
consecutive settings of the instrument. A common form
contains a bit of steel wire to be pushed before the
column and left at the point of maximum temperature, or a
slide of enamel, which is drawn back by the liquid, and
left within it at the point of minimum temperature.
[1913 Webster] Thermometric