809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831
| |

## (sn >to the existing theory of electric and optical phenomena in moving bodies that, in order to explain Michelson’s negative result, the introduction of a new hypothesis has been required, and that the same necessity may occur each time new facts will be brought to light. Surely, this course of inventing special hypotheses for each new experimental result is somewhat artificial. It would be more satisfactory, if if were possible to show, by means of certain fundamental assumptions, and without neglecting terms of one order of magnitude or another, that many electromagnetic actions are entirely independent of the motion of the system. Some years ago, I have already sought to frame a theory of this kind $3. I shall start from the fundamental equations of the theory of electrons I shall now suppose I hat the system as a whole moves in the direction of x with a constant velocity to, and I shall denote bij h any velocity a point of an electron may have in addition to this, so that If the equations (2) arc at the same time referred to axes moving with the system, they become », = «> + u* i>
2) M. E., § 2. | ( 815 ) $ 4. We shall further transform these formulae by a change of variables. Putting ........(3) and understanding by I another numerical quantity, to be determined further on, I take as new independent variables .....(4) .....(5) and I define two new vectors b' and I)' by the formulae tor which, on account of (3), we may also write |