  During the half-century that followed the emergence of unique chemical formulae and viable versions of the kinetic theory around 1860 the content of atomism was clarified and extended and the case for it improved by the development of atomic explanations of experimental effects that involved connections between phenomena of a variety of kinds, the behaviour of gases, the effect of solutes on solutions, osmotic pressure, crystallography and optical rotation, properties of thin films, spectra and so on. In several of these cases atomic explanations were offered of experimental connections for which there were no available alternative explanations so that the case for atomism understood as an inference to the best explanation was strengthened.