# The Readable Dictionary/3 Heat

OF HEAT.
1. Terms relating to the general idea of Heat.
HEAT is the cause of the sensation which we call warmth.
Those who hold the former theory, call the element of heat caloric. They say that caloric exists in two states; first, that of latent (hidden) caloric, in which the caloric is intimately combined with the substance of bodies, and does not affect the thermometer or the sensibility; and second, that of free caloric, in which state the caloric affects the thermometer and produces sensation.
Radiant caloric is a modification of free caloric, and is subject to the same laws that regulate the radiation and reflection of light.
Those who hold the second theory suppose that heat is closely allied to light, and that the rays of heat differ from the luminous rays of any particular color, in the same way that the differently colored rays differ among themselves. Heat and light, they say, depend on undulations in the same elastic ether. The undulations which produce the phenomenon of blue light are supposed to be smaller and more rapid than those which give rise to the phenomenon of yellow light. The undulations from which yellow light results, are again quicker and more limited in their range of motion than those from which red light results; while those which give rise to heat are less frequent, and traverse a wider space than do any of the undulations on which the colored rays depend.
Note 2.—Caloric, or the principle of heat, is the cause of fluidity. Were it not for this principle, all substances—even air—could exist only as solids. It is supposed that a due degree of heat would convert the most refractory solids into liquids, and that under some higher temperature these liquids would be changed into gases.
Note 3.—The sources of heat are the sun, chemical action, and mechanical force.
1. When light proceeds directly from the sun, the rays of light are combined with those of heat; but when solar light is reflected from the moon, it contains no appreciable heat.
2. Whenever substances combine with each other under the influence of chemical affinity, heat is evolved, but not always in such a degree as to affect the thermometer to any appreciable extent; but if substances combine rapidly and with great energy, the heat generated is sometimes very intense, as when water combines with fresh-burned lime.
3. The modifications of mechanical action by which heat may be produced, are friction, (or rubbing,) percussion, (or striking,) and condensation, (or pressing together.)
1st. Friction.—Two sticks of dry wood may be ignited (or set on fire) by rubbing them forcibly together.
2d. Percussion.—If a small piece of iron be placed on an anvil, and be subjected for a few moments to quickly-repeated strokes of a hammer, it will become hot.
Temperature is the condition of a substance in relation to sensible heat.
Note.—When the temperature of a substance is higher than that of my body, it feels warm, because, on touching it, more heat passes from the substance to my body, than what passes from my body to the substance. On the contrary, when the temperature of a substance is lower than that of my body, it feels cold, because, on touching the substance, my body parts with more heat than it receives.
Warm, moderately heated.
Warmth, the sensation caused by heat.
Hot, highly heated.
Tepid, moderately warm; as, a tepid bath.
Temperate, free from the extremes of heat and cold; as a temperate climate.
Ferveo, to boil with heat (L.) Hence,
Fervor, heat; as, the fervor of a summer's day. Fig., great warmth of the kindly affections; as, the fervor of love.
Fervent, hot. (Applied both literally and figuratively.) The elements shall melt with fervent heat. He was animated by a fervent zeal.
Fervid, very warm; as, a fervid radiance; a fervid imagination.
Fervid on the glittering flood, Now the noontide radiance glows.—Cunningham.
Sultry, excessively hot and close. (Spoken of the state of the atmosphere.)
To Swelter is to be overcome and faint with heat.
Torreo, to roast. (L.) Hence,
Torrid, parched with excessive heat; as, a torrid clime.
Caleo, to be hot. (L.) Hence,
Caloric, the element of heat.
Calorific, causing heat.
Note.—Those particular rays of solar light which produce heat are called calorific rays. (L., facio, to cause.)
ΘΕΡΜΟΣ [THERMOS], warm. (Gr.) Hence,
Thermal, 1. Pertaining to, or producing heat; as, thermal rays. 2. Warm or hot; as, a thermal spring.
Thermometer, an instrument for measuring heat. (Gr., μετρεω [metreo], to measure.)
Isothermal, having equal degrees of heat. (Gr., ισος [isos], equal.)
Note.—Isothermal lines on the earth's surface pass through places of equal mean temperature.
Fire is the element of heat.
A Bonfire is a fire made as an expression of public joy. (Fr., bon, good.)
A Balefire is a signal fire.
Sweet Teviot, on thy silver tide The gloomy balefires blaze no more.—Scott.
Ignis, fire. (L.) Hence,
Igneous, 1. Fiery. Sparks emitted from burning substances are igneous particles. 2. Originating in the action of fire.
Note.—Lavas are called igneous rocks from the circumstance of their having been once liquid from heat.
Ignite, to set on fire. A lucifer match may be ignited by friction.
ΠΥΡ [Pyr], fire. (Gr.) Hence,
Pyrometer, an instrument for measuring the intensity of the heat of furnaces. (Gr., μετρω [metreo], to measure.
Pyrotechnics, the art of preparing fire-works for public amusement. (Gr., τεχνη [techne], art.)
Pyroligneous, produced by the action of fire on wood. (L., lignum, wood. )
Note.—Pyroligneous acid is produced by the distillation of wood.
To Burn is to change essentially the nature of a substance by subjecting it to the action of fire.
Comburo [combustum], to burn. (L.) Hence,
Combustion, the particular kind of burning which such substances as wood, coal, and oil undergo when subjected to action of fire.
Combustible, any substance that may be burned after the manner of wood, etc.
A Flame consists of burning vapor.
To Inflame is, 1. To cause to burn with a flame. 2. To cause heat and redness in any part of an animal body. 3. And fig., to excite the ​passions; as, to inflame anger, desire, etc.
To Blaze is to send forth a volume of flame.
To Smoulder is to burn with a smothered combustion, as when the air has not free access to the burning matter.
Flagro [flagratum], to burn with an accompaniment of flame. (L. )
Flagrant, blazing with violence. Used only in a fig. sense; as, a flagrant crime.
Note.—When we thus characterize a crime we imply that it is one which, by its blazing enormity, is calculated to attract general notice.
Conflagration, the burning of a large mass or extended collection of combustibles; as the burning of a forest or of a number of houses in a city. (Con, together.)
Deflagrate, to burn with a sudden and sparkling combustion. Nitre, when thrown on burning coals, will deflagrate.
Incendo [incensun], to set on fire. (L.) Hence,
To In'cense, odorous spices and gums burnt in religious worship.
To Incense', to inflame with anger.
Ardeo [arsum], to burn with great heat. (L.) Hence,
Ardent, burning; as, an ardent fever; an ardent zeal; an ardent desire.
Ardor, a high degree of heat; as, the ardor of the sun's rays. Fig., Great warmth of the commendable affections and passions; as, the ardor of love; to pursue one's studies with ardor.
Arson, the crime of house-burning.
To Set on Fire is to apply fire to any combustible mass or substance, and cause combustion to begin.
To Kindle is to cause combustion to begin and get under way by nursing the incipient flame.
Fuel is any substance that serves as an aliment (or food) for fire. (Fr., feu, fire.)
Tinder is scorched lint used to catch a spark in kindling.
Touchwood is decayed wood that will take fire from a spark produced by striking a piece of steel against a flint. (So called because the touch of a spark will ignite it.)
Punk is a kind of fungus used for tinder.
A Match is, 1. A small bit of pine wood with one end dipped in some chemical preparation that is easily ignited by friction. These are called friction matches. They have likewise been called lucifer matches. 2. A bit of tow, cotton, etc., dipped in sulphur and used in kindling. 3. A piece of hempen cord lighted at one end, and used in firing a cannon.
To Put Out is to cause combustion entirely to cease.
Extinguo [extinctum], to put out. (L.) Hence,
Extinguish, to put out; as, to extinguish a candle. Figuratively, we may speak of extinguishing life or hope.
Note.—When we speak of extinguishing life, we represent it under the figure of a lamp, a live coal, or a spark. Thus we say the lamp of life; or the vital spark.
Extinct, lit, extinguished. (Used chiefly in a fig. sense, as when we speak of life being extinct, or when we say that the mammoth belonged to a species of animals that is now extinct.)
Note.—When we say that a species of animals is extinct, we imply that the vital fire which had been transmitted from generation to generation is gone out, and that the species has ceased to exist.
2. The Products of Combustion.
Note.—Combustibles of a vegetable or animal origin consist chiefly of carbon (the matter of charcoal) and hydrogen, (one of the elements of water.) In combustion the carbon unites with the oxygen of the atmosphere, and forms a gas called carbonic acid, while the hydrogen unites with oxygen and forms water.
Smoke consists of imperfectly burned particles which pass off from burning matter in a visible form.
Note.—When the combustion of wood, oil, etc., is perfect, the mingled vapor and gas pass off in a transparent form, and are, consequently, invisible.
Soot consists of imperfectly burned particles of carbonaceous matter.
Lampblack is soot employed as a paint.
​Ashes consist of the earthy, powder-like matter which remains after the combustion of wood or coal.
Slag is a glassy matter sometimes mingled with the ashes of mineral coal.
Embers are small coals of fire mixed with ashes.
A Cinder is a portion of some animal or vegetable substance reduced, by burning, to the form of a coal. A piece of meat may be burned to a cinder.
Cinis [cineris], ashes. (L.) Hence,
Cineritious, resembling ashes in color; as, the cineritious substance of the brain.
Incinerate, to burn to ashes.
Sparks are small particles of ignited matter emitted from bodies in combustion.
Scintilla, a spark. (L.) Hence,
Scintillate, to emit sparks.
To Bake is to subject a moist substance to a dry heat.
Note.—Soft substances are hardened in baking.
To Roast is to subject a substance, whether moist or dry, to the action of a dry heat.
Note.—We may roast potatoes, coffee, or meat. In metallurgy ores are sometimes roasted for the purpose of driving off the sulphur and other volatile matters with which the ore may happen to be combined.
To Cook is to prepare food by means of heat.
To Fry is to cook a moist substance in a pan without the addition of water.
To Boil is to cook by immersing a substance in boiling water.
To Seethe is to cook by boiling.
Sodden, (past participle of seethe,) cooked by boiling.
To Broil is to cook by placing over burning coals.
To Scorch is to burn so slightly as not essentially to change the texture or chemical composition of a substance.
To Singe is to burn slightly and superficially, as in burning the nap of cloth or the hair of the skin.
To Toast is slightly to scorch by the heat of a fire; as to toast bread or cheese.
To Parch is to render very dry by the action of heat. We may parch corn. The ground may be parched by the heat of the sun. We may be parched with thirst.
To Scald is to affect by the application of hot water.
To Calcine is to reduce by burning to a form resembling that of chalk or burnt lime. Shells and bones may be calcined. (L., calx, lime.)
To Melt is to render liquid by means of heat.
To Thaw is to melt ice, or to soften by heat that which has been frozen.
4. Of the action of Heat on Liquids.
Boiling consists in the formation, by heat, of bubbles filled with vapor.
Ebullition is the action of boiling. (L., ebullio, to boil, from bulla, a bubble.)
To Seethe is to be in a state of ebullition; as, a seething cauldron.
To Simmer is to boil gently.
To Effervesce is to boil without heat, in consequence of a rapid formation and escape of bubbles of gas. (L., ef for ex, forth; and ferveo, to boil.)
5. Of Cold.
COLD is the privation of heat.
Cold is also the sensation caused by the escape of heat from the body.
Cold, (adj.,) having a temperature much below that of our bodies.
Cool, having a temperature slightly below that of our bodies.
Lukewarm, having a temperature equal to that of our bodies. (Spoken of liquids.)
To Freeze, when spoken of water, signifies to pass from a liquid to a solid state, in consequence of the escape of caloric.
To Freeze, when spoken of animals ​or plants, signifies to perish through intense cold.
Frigeo, to freeze. (L.) Hence,
Frigid, very cold; as, the frigid zone.
Gelu, frost. (L.) Hence,
Gelid, as cold as ice. (Applied to water.)
Congeal, to change into ice.
Congelation, the act of changing into ice.
Bleak, exposed by situation to cold winds.
6. The Attributes of Cold.
When we say that the cold air, or cold wind is sharp, cutting, keen, or piercing, these are figurative forms of expression, in which there is an allusion to cutting and piercing instruments. The figure is founded on the similarity of the sensation caused by cold wind to the sensation caused by the application of the keen edge of a razor, or the sharp point of a needle to the skin.
When we speak of cold as being intense, the literal allusion is to the idea of a strained bow-string. (L., intendo [internum], to strain.)