Dalton’s Long Journey from Meteorology to the Chemical Atomic Theory

Abstract

The purpose of this paper is to review Dalton’s contributions to science in various fields of research in relation to the first intimation of the chemical atomic theory. Early “germs” of his physical ideas may be found in the initial meteorological studies where water vapour is viewed as an “elastic fluid sui generis” diffused in the atmosphere and not as a species chemically combined with the other atmospheric gases. The next object of Dalton’s attention was atmosphere itself. He discarded affinity between atmospheric gases as a possible cause of homogeneity and, making recourse to Newtonian Principles, considered the repulsive forces among particles. Experiments on the “nitrous air test” and on the diffusion and solubility of gases were instrumental to arrive at the chemical atomic theory. The slow, laborious, and persevering work of Dalton to get the first table of atomic weights is a fascinating piece of science which may be fully appreciated by referring to his laboratory notebooks.