thermically 
The cases hitherto reported hardly justify positive state- 
ments as to the exact situation of thermieaUy active 
nerves. Medical A'eics, LII. 567. 
thermidt, adr. A Middle English form of there- 
mid. 
Thermidor (ther-mi-ddr'; F. pron. ter-me-d6r'), 
n. [< F. tliermidor, irreg. < Gr. Kp/iri, heat, + 
Sopov, gift.] The eleventh mouth of the French 
republican calendar (see calendar), beginning, 
in 1794, on July 19th, and ending August 17th. 
Thermidorian (ther-mi-do'ri-an), a. and n. [< 
F. thermidorieii ; as Thermidor + -i-an.] I. a. 
Of or pertaining to the Thermidorians. See II. 
II. . One of the more moderate party in the 
French revolution, who took part in or sympa- 
thized with the overthrow of Robespierre and 
his adherents on 9th Thermidor (July 27th), 
1794. 
thermo-aqueous (ther"mo-a'kwe-us), a. [< Gr. 
dep/u?i, heat, + L. aqua, water:' see aqueous."] 
Of or pertaining to heated water, or due to its 
action. 
thermobarograph (ther-mo-bar'o-graf), n. [< 
Gr. Bf/j/ai, heat, + E. barograph."] An appara- 
tus combining a thermograph and a barograph 
in one interdependent instrument. 
thermobarometer (ther"mo-ba-rom'e-ter), n. 
[< Gr. Sspiiii, heat, + E. barometer.] 1. A ther- 
mometer which indicates the pressure of the 
atmosphere by the boiling-point of water, used 
in the measurement of altitudes. 2. A siphon- 
barometer having its two wide legs united by 
a narrow tube, so that it can be used either in 
its ordinary position as a barometer or in the 
reversed position as a thermometer, the wide 
sealed leg of the barometer then serving as the 
bulb of the thermometer. 
thermo-battery (ther'mo-bat'er-i), H. A ther- 
mopile. 
thermocautery (ther-mo-ka'ter-i), .. [< Gr. 
Bcpftr/, heat, + E. cautery.] A form of actual 
cautery in which the heat is produced by blow- 
ing benzin-vapor into heated spongy platinum 
on the inside of the cauterizing platinum-point. 
thermochemical (ther-mo-kem'i-kal), a. [< Gr. 
Oepfai, heat, + E. chemical.] Of or pertaining to 
thermochemistry, or chemical phenomena as 
accompanied by the absorption or evolution of 
heat. 
thermochemist (ther-mo-kem'ist), . [< Gr. 
6cpfj.ii, heat, + E. chemist.] One who is versed 
in the laws and phenomena of thermochemis- 
try. Nature, XLIII. 165. 
thermochemistry (ther-mo-kem'is-tri), . [< 
Gr. Uipftn, heat, + E. chemistry.] That branch 
of chemical science which includes all the va- 
rious relations existing between chemical ac- 
tion and heat. 
thermochrose (ther'mo-kros), . Same as 
thermochrony. 
thermochrosy (ther'mo-kro-si), n. [< Gr. Bfpiai, 
heat, + xpuatf, coloring, < xpa&iv, touch, impart, 
tinge, color: see chromatic.] The property pos- 
sessed by radiant heat of being composed, like 
light, of rays of different refraiigibilities, vary- 
ing in rate or degree of transmission through 
diathermic substances. This property follows from 
the essential identity of the invisible heat-rays of rela- 
tively long wave-lengths and the luminous rays, or light- 
rays. Sometimes called heat-color. See radiation and 
spectrum. 
thermo-COUple (ther'm6-kup"l), H. [< Gr. Btpfui, 
heat, + E. couple] A thermo-electric couple. 
See thermo-electricity. Philos. Mnq., 5th ser., 
XXIX. 141. 
thermo-current (ther'm6-kur"eut), n. [< Gr. 
ffep/ttl, heat, + E. current 1 .] The current, as 
of electricity, set up by heating a compound 
circuit consisting of two or more different 
metals. 
thermod (ther'mod or -mod), n. [< Gr. Bepfiri, 
heat, + od 3 .] Thermic od; the odic or odyllic 
force of heat. See od s . Von Beichenbach. 
thermodynamic (ther"mo-di-nam'ik), a. [< Gr. 
Oepttq, heat, + 6vva/Mt;, power: see dynamic.] 
Relating to thermodynamics; caused or oper- 
ated by force due to the application of heat. 
Thermodynamic function. See function. 
thermodynamical (ther'mp-dl-nam'i-kal), a. 
[< thermodynamic + -al.] Of or pertaining to 
thermodynamics. Philos. Mag., 5th ser., XXVII. 
thermodynamically (ther // mo-di-nam'i-kal-i), 
adv. In accordance with the' laws of thermo- 
dynamics. Jour. Franklin Inst., CXXVIII. 467. 
thermodynamicist (ther"mo-di-nam'i-sist), n. 
[< thermodi/namic + -ist.] A student of ther- 
modynamics; one versed in thermodynamics. 
6282 
The mechanical equivalent of heat the familiar " J" 
of thennodynamicists. The Academy, Oct. 26, 1880, p. 273. 
thermodynamics (ther"mo-di-nam'iks), n. [Pi. 
of thermodynamic (see -ics).~] The general math- 
ematical doctrine of the relations of heat and 
elasticity, or of temperature, volume, pressure, 
and mechanical work. The consideration of moving 
forces, though suggested by the form of the word, does 
not enter into the subject to any considerable extent. 
Thermodynamics. In a strict interpretation, this branch 
of science, sometimes called the Dynamical Theory of 
Heat, deals with the relations between heat and work, 
though it is often extended so as to include all transfor- 
mations of energy. Either term is an infelicitous one, for 
there is no direct reference to force in the majority of 
questions dealt with in the subject. 
Tail, Encyc. Brit., XXIII. 283. 
Laws of thermodynamics. The first law is the propo- 
sition that a given amount of heat measured by the pro- 
duct of the absolute temperature, the mass heated, and 
its specific heat is equivalent to and correlated with a 
given amount of mechanical work measured by the pro- 
duct of a force (as the mass of a body multiplied by the 
acceleration of gravity) into a distance through which 
the point of application is driven back against the force. 
The second law is the proposition that heat tends to flow 
from a hotter to a colder body, and will not of itself flow 
the other way. 
The principle of the conservation of energy when applied 
to heat is commonly called the First Law of Thermody- 
namics. It may be stated thus: when work is transformed 
into heat, or heat into work, the quantity of work is me- 
chanically equivalent to the quantity of heat. Admitting 
heat to be a form of energy, the second law asserts that it 
is impossible, by the unaided action of natural processes, 
to transform any part of the heat of a body into mechani- 
cal work, except by allowing heat to pass from that body 
into another at a lower temperature. 
Clerk Maxwell, Heat, p. 152. 
thermo-electric (ther"mo-e-lek'trik), a. [< Gr. 
Kpfj-tl, heat, + E. electric.] ' Pertaining to ther- 
mo-electricity : as, thermo-electric currents. 
Thermo-electric alarm, an electrical apparatus de- 
signed to indicate the rise of temperature beyond a cer- 
tain desired point, as, for instance, to show when the 
bearings of shaftings are overheated, or when a room is 
too warm from overheating or in danger from fire. 
Thermo-electric couple. See thermo-electricity. Ther- 
mo-electric force, the electromotive force produced by 
a thermo-electric couple, or thermopile. Thermo-elec- 
tric height. See the quotation. 
The name " thermoelectric height "has been introduced 
to denote the element usually represented by the ordi- 
nates of a thermoelectric diagram. 
J. D. Everett, Units and Physical Constants, Pref., ix. 
Thermo-electric multiplier, the combination of a ther- 
mopile and a galvanometer as a 
set of apparatus for the measure- 
ment of differences of tempera- 
ture of radiant heat, etc. Ther- 
mo-electric series. See thermo- 
electricity. 
thermo-electrically (ther"- 
mo-e-lek'tri-kal-i), adv. In 
accordance with the laws of 
thermo-electricity. Encyc. 
Brit., VIII. 94. 
thermo-electricity (ther"- 
Tno-e-lek-tris'i-ti). n. [< Gr. 
ffep/ii/, heat, + E. electricity."] 
The electric current pro- 
duced in a circuit of two or 
more dissimilar metals, or 
in a circuit of one metal different parts of 
which are in dissimilar physical states, when 
one of the points of union 'is heated or cooled 
relatively to the remainder of the circuit; also, 
the branch of electrical science which treats of 
electric currents so produced. If, for example, a 
bar of bismuth and one of antimony are soldered toge- 
ther and the point of union is heated while their other 
extremities are connected by a wire, it is found that an 
electric current passes from bismuth to antimony, and 
through the wire from antimony to bismuth. Such a pair 
of metal bars is called a thermo-electric couple or pair, and 
it is found that the 
thermo - electromo- 
tive force, as it is 
called, is, for a cir- 
cuit composed of the 
same pair of metals, 
proportional to the 
difference of temper- 
ature between the 
hot and the cold 
junction. It is found, 
further, that it dif- 
fers for different metals ; and the list of the metals, ar- 
ranged in order according to the direction of the current 
generated, is called the thermo-electric series (analogous to 
the electromotive series in voltaic electricity) : for exam- 
ple, bismuth, lead, zinc, copper, iron, antimony. If more 
than one couple are employed, the whole electromotive 
force is the sum of the separate forces for the successive 
junctions. A number of couples of the same two metals 
joined together form a thermo-electric battery, or ther- 
mopile ; they are arranged so that one set of junctions can 
be heated while the other is kept cool. When connected 
with a delicate galvanometer, the thermopile can be used 
to detect and measure very small differences in tempera- 
ture, as especially small differences in radiant heat; for 
this purpose one end of the thermopile is generally coat- 
Thermo-electric Multi- 
plier. 
thermograph 
ed with lampblack so as to absorb the heat incident upon 
it, and a cone of polished brass may be added to collect 
more heat. Thermo-electric couples give a comparatively 
low electromotive force, which has, however, great con- 
stancy if the two sets of junctions are kept at a uniform 
temperature. What is called the Peltier phenomenon or 
effect is the rise or fall of temperature at the junction of 
two different metals due to the passage of an electric 
current from one metal to the other across the junction. 
This thermal effect is distinct from the rise of tempera- 
ture due to the electrical resistance of the metals, and 
changes sign when the direction of the current across the 
junction is changed. 
thermo-electrometer (ther"mo-e-lek-trom'e- 
ter), n. [< Gr. Oipfi?/, heat, + E. electrometer.] 
An instrument for ascertaining the heating 
power of an electric current, or for determin- 
ing the strength of a current by the heat it pro- 
duces. 
therm o-electromotive(ther"m6-e-lek-tro-m6'- 
tiv), a. [< Gr. 6ep/jr/, heat, + E. electromotive."] 
Pertaining to thermo-electricity Thermo-elec- 
tromotive force. Same as thermo-electric force (which 
see, under thermo-electric). 
thermo-element (ther"m6-ere-ment), n. A 
thermo-electric couple. See thermo-electricity. 
thermo-excitory (ther"m6-ek-si't9-ri), a. [< 
Gr. Oepfir/, heat, + E. excite + -ory.~] Causing 
the production of heat in the body. 
thermogent (ther'mo-jen), n. [< Gr. Bipfir/, heat, 
+ -yevi/f, producing: see -gen.] The fluid for- 
merly supposed to exist which was known as 
caloric (which see). 
thermogenesis (ther-mo-jen'e-sis), n. [< Gr. 
0?p[u;, heat, + yevfaif, production.] The pro- 
duction of heat; specifically, the production 
of heat in the human body by physiological 
processes. 
thermogenetic (ther"mo-je-net'ik), a. Same 
as thermogenic. Boston Med. and Surg. Jour. 
thermogenic (ther-mo-jen'ik), n. [As therma- 
e/en + -ic.] Of or pertaining to the production 
of heat ; producing heat Thermogenic centers, 
nervous centers whose function is to stimulate the pro- 
duction of heat in the body. Thermogenic fibers, ner- 
vous fibers conveying impulses which increase the produc- 
tion of heat in the body. Thermogenic substance, a 
substance which is associated with the production of heat 
in the body. 
thermogenous (ther-moj'e-nus), a. [As ther- 
mogen + -os.] Producing heat. 
thermogram (ther'mo-gram), . [< Gr. 6tp/ai, 
heat, + ^pafifia, a mark, writing.] The record 
made by a thermograph. 
thermograph (ther'mo-graf), . [< Gr. Sepfiii. 
heat, T fp&ttiv, write.] An automatic self- 
registering thermometer. A variety of forms have 
been used, involving different principles and methods, 
(a) In the photographic method mercurial thermometers 
are used in the following manner : near the top of the 
mercury in the stem an air-bubble separates the column ; 
by the action of a system of lenses the light from a lamp 
passes through the air-bubble, and throws the image of 
the bubble on the surface of a revolving cylinder upon 
which is wrapped a sheet of sensitized paper; no other 
light except the ray passing through the bubble enters 
the dark chamber containing the cylinder, and a photo- 
graphic registration is therefore made of the oscillations 
of the mercury-column. (6) In the metallic thermograph 
the actuating instrument is a metallic thermometer whose 
indications are made to yield any desired degree of sensi- 
tiveness by a lever or levers which give motion to a re- 
cording pen. To an iron frame (see the cut) are fastened 
the thermometer-strips, the clock, the adjustments of 
the recording lever, and the perforated protecting case. 
The clock rotates a metallic disk once a week. A paper 
chart is fastened to the disk and rotates with it. The chart 
is divided into fourteen equal spaces, the dark spaces in- 
dicating night-time. These spaces are subdivided to 
indicate hours. The recording lever traces with an ink 
pen a line upon the paper chart, according as the metallic 
thermometer bends as affected by the heat or cold. The 
Thermo-electric Couple. 
thermometer is composed of two strips of metal of differ- 
ent expansibilities. The curve thus traced over the con- 
centric lines of the paper chart which indicate degrees 
