857 



fomponents of a genuine quantity of second order obtain (lie 

 factor T~'^. Wlien the current vanishes, this quantitj has the same 

 character as the variable fnndanienta! tensor of Wkyi/s theory, and 

 — 2 S'x behaves as the vector whicii Weyl calls (f.^. 



4. On the hiu) of conservation of energy and momentum. The law 

 of conservation of energy and monientiim in gravitation llieoi'y is 

 a coiise(|nence of the identity of Hianchi. The form of this identity 

 is known for non-symmetrical displacements and for displacements 

 with non-invariant transvection '). Hence it mnst be possible to 

 deduce, starling with this identity, an equation that can be considered 

 as an analogon of the equation that expresses (he law of energy 

 and momentum. This possibility exists already before any supposition 

 is made relating (o the special form of Hamilton's function. 



1) Cf. Math. Zeitschrift 1923, 17, p. Ill — 115; R. VVeitzenböck, Invarianlentheorie 

 (NooRDHOFF, Giüiiingen 1923), p. 857. 



