|Top: The basic outline of Boerhaave's law, which states that adding heat Q to a body will cause volume expansion and that removal of heat will cause volume contraction, enunciated as a general law of nature in 1720 by Dutch physical chemist Herman Boeraave; a principle that formed the basis of French chemist Antoine Lavoisier's 1787 caloric theory; which, in turn, formed the basis for French physicist Sadi Carnot's 1824 general theory of the operation of heat engines; which, in turn, formed the basis of German physicist Rudolf Clausius' 1865 The Mechanical Theory of Heat, and thus the science of thermodynamics and the two central laws of universal operation, namely energy conservation (first law) and entropy increase (second law). Bottom (right): example of Boerhaave's law in metals: rail length expansion and subsequent rail buckling due to hot weather (heat). Bottom (left): modern tracks use "gaps" to prevent the buckling of tracks during hot weather.|
“Air extends and expands itself more or less according to a greater or lesser intensity of heat. Warm air, consequently, occupies a larger space and cold a smaller.”— Otto Guericke (1663), Magdeburg Experiments on the Vacuum of Space
“The property of expansion with heat, and contraction with cold, is not peculiar to liquors only, but to all kinds of solid bodies, especially metals.”— Robert Hooke (1665), Micrographia (pg. 39); post-dates Otto Guericke equivalent statement; pre-dates Boerhaave’s law (c.1720), which is cited by Antoine Lavoisier (1789) as the basis of his caloric theory
See main: Papin engineIn 1690, French physicist Denis Papin published his "A New Method to Obtain Very Great Motive Powers at Small Cost" wherein he conceived the view that he could utilize the expansive properties of water by heat to make a piston and cylinder lift weight using fire, the gist idea of which he outlines as follows:
“Since it is a property of water, that a small quantity of it turned into vapor by heat has an elastic force like air, but upon cold supervening is resolved again into water, so that no trace of the said elastic force remains … [thus] I at once saw that machines could be constructed, in which water, by the help of a moderate heat, and a little cost, might produce that perfect vacuum.”
|Left: the Papin engine operated via the action of Boerhaave's law. Right: a depiction of the famous "ball and ring experiment" famously performed in circa 1730 by Dutch physicist Willem Gravesande, at Leyden University, to the amazement of crowds in excess of 500, being that the phenomena was contrary to the prevailing theories of matter and heat and their operations.|
(a) The same degree of fire rarefies fluids sooner, and in greater degree, than it does solids. Without this law, the thermometer would be useless, since the cavity of the tube would then be dilated in the same proportion as the fluid is rarefied.
(b) The lighter the fluid, the more it is dilated by fire. Air, the lightest of fluids known (to Boerhaave), expands the most; after air, spirit of wine.
(c) All the motion in nature arises from fire alone; taking this away, all things become immovable. At the absence of only a certain degree of fire, all oils, waters, spirits, vegetables, and animals, become hard, rigid, and inert. If the greatest degree of cold was arrived at, and all fire was absolutely taken away, all nature would grow into one concrete body, sold as gold and hard as diamond: on the reapplication of fire it would recover its former mobility.
|Left: a "social volume" piston and cylinder view of society "worked" according to the operation of Boerhaave's law each day when heat from the sun is put into each social system on the surface of the earth, thus causing volume expansion (social volume expansion), otherwise known as daily work. Right: a Mean Girls depiction of Boerhaave's law at work in the operation of human chemical reactions, wherein reaction heat causes volume expansion, when the alpha female walks though the hall of a local high school and the student contract backwards giving her more personal space.|
“That every body, whether solid or fluid, is augmented in all its dimensions by any increase of its sensible heat, was long ago fully established as a physical axiom, or universal proposition, by the celebrated Boerhaave.”
“All substances in nature can be employed for this purpose, all are susceptible of changes of volume, of successive contractions and dilatations, through the alternation of heat and cold. All are capable of overcoming in their changes in volume certain resistances, and of thus developing the impelling power.
A solid body—a metallic bar for example—alternately heated and cooled increases and diminishes in length, and can move bodies fastened to its ends. A liquid alternately heated and cooled increases and diminishes in volume, and can overcome obstacles of greater or less size, opposed to its dilatation.
|Phase change diagram for water on going from solid-to-liquid-to-vapor, with corresponding increase in volume, according to Boerhaave's law as heat is added; the horizontal sections, enthalpy of fusion Hf and enthalpy of vaporization Hv, to note, correspond to the points at which latent heat is added.|
An aeriform fluid is susceptible of considerable change of volume by variations of temperature. If it is enclosed in an expansible space, such as a cylinder provided with a piston, it will produce movements of great extent. Vapors of all substances capable of passing into a gaseous condition, as of alcohol, of mercury, of sulphur, etc., may fulfill the same office as vapor of water.
The latter, alternately heated and cooled, would produce motive power in the shape of permanent gases, that is, without ever returning to a liquid state. Most of these substances have been proposed, many even have been tried, although up to this time perhaps without remarkable success.”