In 1783, Antoine Lavoisier and Pierre Laplace, in their Memoir on Heat, building on the former "phlogiston" model of heat, introduced a new model, based on recent experiments with their "calorimeter", a device they built to measure the amount of heat released or absorbed during chemical reactions, wherein heat was defined as fluid like particles, with no mass, that could penetrate all bodies in the universe, and thereby produce volume expansion.
In 1787, Antoine Lavoisier, Guyton Moreau, Claude Berthollet, and Antoine Fourcroy, in a joint paper on chemical nomenclature reformulation, introduced the term "caloric" for as the name of the Lavoisier-Laplace heat particle..
Caloric | Sand model
In 1789, Lavoisier, in his Elements of Chemistry, introduced a "spherical lead bullets and sand" model to represent the atoms and caloric of bodies. In this model, any body of the universe is defined as being built of so many spherical lead bullets. When heat, in the form of hypothesized sand-like caloric particles, is introduced into this bullet framed body, it causes the body to expand in volume, according to Boerhaave's law (c.1720s), which then was experimentally evidenced by the Papin digester (1679). Likewise, heat or caloric released from bodies, causes volume contraction.
In 1805, Jane Marcet, in her Conversations on Chemistry, building on Lavoisier's sand model of caloric, introduced a sand-marble illustrative model of capacity of a body for caloric, in which the sand represents the "caloric" and the ping pong balls represent the atoms, according to which a given body will have so much capacity for caloric, i.e. heat as it was viewed in that period:
Here, Marcet, to clarify, is using "sand as caloric" to explain what we now call "heat capacity".
- Papin digester – Hmolpedia 2020.
- Morveau, Guyton. (1787). Method of Chemical Nomenclatur (Méthode de Nomenclature Chimique) (pg. 31). Publisher.
- Lavoisier, Antoine. (1789). Elements of Chemistry (pg. 16). Dover.
- Boerhaave’s law – Hmolpedia 2020.
- Marcet, Jane. (1805). Conversations on Chemistry (pg. 66). Philadelphia: Grigg & Elliot, 1846.
- Caloric – Hmolpedia 2020.