Expression of the equation of state of gases and liquids by means of series.”

Abstract

I have followed in this communication a different method in considering the equation of state than has been done up to now. Yarious methods have been tried to empirically derive functions of v and t for van der Waals’s a and b by means of kinetic or thermodynamic considerations, but without obtaining a good agreement with the observations over the whole range of the equation of state. Neither was I successful in similar attempts which were repeatedly occasioned by my continued research on the corresponding states and other investigations resulting from them at the Leiden laboratory. Whenever I seemed to have found an empirical form, I discovered after having tested it more closely that it appeared useful only within a limited range to complete what had been found in a purely theoretical way by van der Waals and Boltzmann. Hence it appeared to me more and more desirable to combine systematically the entire experimental material on the isothermals of gases and liquids as independently as possible from theoretical considerations and to express them by series.