2 2 6 D O C U M E N T 2 2 9 J U N E 1 9 2 8 , where the are 4 well-defined constant matrices, and that holds. This correspondence can be followed for another round, and we want to answer the following question, without any physical ulterior motives: for given , owing to 1a.), the are not at all determined we seek differential covariants of the which are not affected by that lack of determinacy, and which in the end depend only on the . It is clear that we will thus be led to irrational fundamental covariants. The general solution to 1a) can be seen to be: , where S represents an orthogonal transformation: . In fact, we find . Which transformations are then undergone by the ? or, more compactly as matrices, 4.) . Now, from 3.), we have: and thus, if we take the following identity: we obtain 5.) , that is, we set and obtain 7.) . 2)   ··  p   h. = p  1 2 p  p l p l p  +    l = g  h  .  h  .  g  3.) H SH = 3a.) S –1 S' = G H'S'SH H'H   G =           x   =    h .  * x  h  ·· .    ------------    H –1 x  - H –1 H x  - –H    -----------  H x  S H x  -------- S x  -------- H  +   –1 S x  -------- S' x  -------- S   –S    H –1 S' x  -------- S     H + = 6. Q  H  H –1  Q S' –1 Q  S' S' –1 S' x  -------- + =