Chapter Thermochemic to Thick of T by Webster's Dictionary (1913 Edition)

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 Réaumur.

To reduce degrees Fahrenheit to degrees Centigrade, substract 32° and multiply by &frac59; to reduce degrees Centigrade to degrees Fahrenheit, multiply by &frac95 and add 32°.

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.

Thermometric
(Ther`mo*met"ric Ther`mo*met"ric*al) a. [Cf. F. thermométrique.]

1. Of or pertaining to a thermometer; as, the thermometrical scale or tube.

2. Made, or ascertained, by means of a thermometer; as, thermometrical observations.

Thermometrically
(Ther`mo*met"ric*al*ly) adv. In a thermometrical manner; by means of a thermometer.

Thermometrograph
(Ther`mo*met"ro*graph) n. [Thermo- + Gr. measure + -graph.] (Physics) An instrument for recording graphically the variations of temperature, or the indications of a thermometer.

Thermometry
(Ther*mom"e*try) n. The estimation of temperature by the use of a thermometric apparatus.

Thermomultiplier
(Ther`mo*mul"ti*pli`er) n. [Thermo- + multiplier.] Same as Thermopile.

Thermopile
(Ther"mo*pile) n. [Thermo- + pile a heap.] (Physics) An instrument of extreme sensibility, used to determine slight differences and degrees of heat. It is composed of alternate bars of antimony and bismuth, or any two metals having different capacities for the conduction of heat, connected with an astatic galvanometer, which is very sensibly affected by the electric current induced in the system of bars when exposed even to the feeblest degrees of heat.

Thermoscope
(Ther"mo*scope) n. [Thermo- + - scope.] (Physics) An instrument for indicating changes of temperature without indicating the degree of heat by which it is affected; especially, an instrument contrived by Count Rumford which, as modified by Professor Leslie, was afterward called the differential thermometer.

Thermoscopic
(Ther`mo*scop"ic) a. (Physics) Of or pertaining to the thermoscope; made by means of the thermoscope; as, thermoscopic observations.

Thermostat
(Ther"mo*stat) n. [Thermo- + Gr. to make to stand.] (Physics) A self-acting apparatus for regulating temperature by the unequal expansion of different metals, liquids, or gases by heat, as in opening or closing the damper of a stove, or the like, as the heat becomes greater or less than is desired.

Thermostatic
(Ther`mo*stat"ic) a. (Physics) Of or pertaining to the thermostat; made or effected by means of the thermostat.

Thermosystaltic
(Ther`mo*sys*tal"tic) a. [Thermo- + systaltic.] (Physiol.) Influenced in its contraction by heat or cold; — said of a muscle.