An approximate determination of the boiling points of metals

Despite the facility with which high temperatures can be reached and maintained constant by means of electric heating, no general investigation of the boiling points of the metals has yet been carried out, and such information as is available has in many cases been obtained by considerable extrapolation. Moreover, the published data are remarkably discordant, as will be seen from the individual results quoted below. In the course of an extended experimental investigation, H. Moissan has made observations on the vaporisation of metals at high temperatures by observing the loss of weight of a considerable mass of metal heated for definite periods of time in his arc furnace. O. P. Watts has attempted to deduce from these experiments approximate values for the boiling points of the metals. In addition to the uncertainty due to the fact that many metals possess a high vapour tension at temperatures much below their actual boiling points, considerable errors are caused by the fact that Moissan does not appear to have measured the expenditure of energy in the furnace, which varies widely according to the conductivity of the vapours surrounding the arc. Also, in many of his experiments the temperature of ebullition must have been altogether modified by carburisation.