6 4 D O C U M E N T S 5 1 , 5 3 S E P T E M B E R 1 9 2 7 51. To Gotthold Mamlock[1] Berlin, 16 September 1927 Dear Mr. Mamlock, I greatly regret not being able to fulfill your wish.[2] A review which would be sufficiently detailed that I would be completely convinced of having expressed my opinion precisely would be more difficult and more time-consuming to write than if I were to treat the topic myself. But for the latter course, I am at present lacking in both the requisite time and motivation, since it is rather useless to oppose a sci- entific opinion when one does not have sufficient logically justified evidence for a better, differing opinion. Respectfully yours, 52. From Oswald Veblen[1] 16 September 1927 [See documentary edition for English text.] 53. To Chaim Herman Müntz[1] [between January 1927 and 17 September 1927][2] Dear Dr. Müntz, The equation that I suggested is indeed mainly covariant. In fact, the canonical equations are covariant. If one restricts oneself to transformations under which is invariant, then, because of the first system of canonical equations, the expression dt dq i H p i ------- = dt dp i H q i –------- = i pidqi H p i pi-------