2 3 4 D O C U M E N T 3 0 2 J U L Y 1 9 2 2 lifetime which is long compared to the emission process and not short anymore compared to the mean collision time? Perhaps all the earlier questionable points are consequently moot? P. P. 301. From Hermann Struck Königstein i. T., Falkensteinerweg 6, 19 July 1922 [Not selected for translation.] 302. To George Jaffé Berlin, 22 July 1922 Dear Colleague, To your letter of the 17th of this mo.[1] I would like to reply the following: 1) If one upholds that in the general theory of relativity should be the expression for the conservation laws[2] (which one definitely must), then should be regarded as the expression for the energy momentum[3] of a finite, Gali- lean embedded system.[4] Permitting only linear transformations, is a covariant vector, as is a tensor density (of first order) is a first-order tensor (covariant vector) Likewise the integral. Through integration it follows that is a covariant vector, hence also itself. For the case of a mass point, therefore, ∂xν ∂ Tμ ν tμ ν + ( ) 0= Tμ ν tμ ν + ( ) Aμν = Aμ 4 x1dx2dx3= d Iμ Iμ ∂xν ∂ Tμ ν tμ ν + ( ) ∂xν ∂ Tμ ν tμ ν + ( )dx1dx2dx3dx4 Iμ t1 t2 Iμ Iμ= m0gμαdsα dx