Abstract

Based largely on unpublished manuscript material from the Kelvin papers, and especially on a series of letters exchanged in 1867 between Fleeming Jenkin and William Thomson , this paper aims to examine the background and content of the Thomson-Jenkin speculations on the nature of matter. The letters formed an interlude in a long collaboration over electrical patents and raise the fundamental question of whether these speculations, involving the construction of a variety of conceptual models, derive primarily from older traditions of speculative matter theory, or from contemporary problems within natural philosophy qua physics. The correspondence also provided the immediate background to Jenkin's North British review article of 1868 on ‘Lucretius and the atomic theory’