## Essay towards the calculus of functions. Part 2.

This is the second paper by Nordstr{o}m on his five dimensional theory. It aims at generalizing the relations $\mathbf{D} = \epsilon \mathbf{E}$, $\mathbf{B} = \mu \mathbf{H}$ of electromagnetism to the five dimensional gravito-electric theory and to show that this is consistent with the principle of equivalence. Some steps are taken toward providi...

This is the third paper by Nordstr{o}m on his five dimensional theory. Here Nordstr{o}m attempts to base a theory of matter on the energy conservation generalized to the five dimensional case. This involves a new fundamental constant related to the elementary electric charge.

The problems in variation here concerned are such as to admit a continuous group (in Lie's sense); the conclusions that emerge from the corresponding differential equations find their most general expression in the theorems formulated in Section 1 and proved in following sections. Concerning these differential equations that arise from problems of ...