The Energies of Natural Alpha Particles

The paper gives recalculated values of the energies of natural alpha particles which have been measured precisely by deflection methods. The results are based on the new values for the Faraday and the mass of the ${\mathrm{He}}^4$ atom, a revised value for the author's absolute determination of the main group of RaC' and weighted mean values for the main groups of Th${\mathrm{C}}^{212}$, Th${\mathrm{C}\text{'}}^{212}$, and ${\mathrm{Po}}^{210}$.