ABSTRACT
Scientific theories are very rarely born out of the blue, and the atomic theories of the nineteenth century have their roots in the writings of scientists of the seventeenth and eighteenth centuries. It may be helpful to have such explanations; for instance theoretical chemists today explain chemical reactions in terms of electrons, orbitals, and wave equations even though these theories can provide only post hoc explanations, rather than predictions, in all but the simplest cases. Chemists should be plain blunt men, keeping their feet on the ground, and in their science all that it was necessary to know was that some substances could not be further analysed. With the progress of the science, the list of elements might change as some yielded to more powerful techniques. The major difficulty of the Boscovich atom was that it was an abstruse idea, much harder to visualise than a billiard-ball atom.
