|Scottish metaphysician James Ferrier’s circa 1850 opening synopsis (Ѻ) of the “atomic school”, from his Lectures on Greek Philosophy.|
Greek | Atomic school
The predominate usage of the term “atomic school”, prior to the 18th century, tends to refer to the Greek atomic theorists: namely: Leucippus, Democritus and Epicurus and their adherents, e.g. Lucretius.
Heat | Atomic school
In the 19th century, in reaction to the Lavoisier argument that heat was a type of fluid like atom termed caloric, the term “atomic school” began to be associated with Maxwell, Clausius, and Boltzmann, according to which atoms viewed as real and heat was conceptualized as matter in motion; as opposed to others, such as the “energetics school”, e.g. Ernst Mach, who denied the existence of atoms, believing instead that "all is energy" and or that an atom was a point center of force as Roger Boscovich believed, i.e. an "all is force" philosophy. (Ѻ)
The following are related quotes:
“Nay, even that school which is most accused of atheism doth most demonstrate religion; that is, the school of Leucippus and Democritus and Epicurus. For it is a thousand times more credible, that four mutable elements, and one immutable fifth essence, duly and eternally placed, need no god, than that an army of infinite small portions, or seeds unplaced, should have produced this order and beauty, without a divine marshal.”— Francis Bacon (c.1601), “Of Atheism” 
“Atomism ‘flourished’ in Greece for a period of about 150-years, from 430 BC to 280 BC. During the whole of this period there was something like an ‘atomic school’, working at the theory, handing down traditions and developing new points with greater or less activity, but three great names stand out as landmarks in the course of its evolution, those of Leucippus, Democritus and Epicurus.”— Cyril Bailey (1928), The Greek Atomists and Epicurus (pgs. 1-2) 
● Atomic theory
1. Bacon, Francis. (c.1610). “Of Atheism”, Publisher.
2. Bailey, Cyril. (1928). The Greek Atomists and Epicurus: a Study (Ѻ)(pdf). Russell & Russell, 1964.