2 0 2 D O C U M E N T S 2 4 9 , 2 5 0 J U N E 1 9 2 2 249. From Mathilde Rathenau [Berlin, after 24 June, 1922] Esteemed Professor, Among the thousands of letters, there are only a few that I answer personally— let this say more to you than words. My son often told me about his conversations with you I know what he thought of you and so please retain his memory in its old purity he is second to none in the whole wide world. Only God knows what he meant to me! Mathilde Rathenau 250. From Hermann Anschütz-Kaempfe Kiel, 25 June 1922 Dear, esteemed Professor Einstein, Many thanks for your letter of the 18th inst. it is kind of you to occupy yourself so much in thinking about the floating sphere and all that is associated with it. Your suggestions regarding a metallic salt solution and the same metal as the electrode had already seemed viable to us as well but had proved impossible for Cu as well as for Ag the solution does not stay pure electrode compounds evidently occur that do not reduce anymore. Carbon in H2O + H2SO4 has been the best by far, the latter c. 0.5% the liquid stayed clear and unchanged with a current passing through it for months. Such things are much more easily and productively discussed in person, of course I do have another interesting question about the surveying-compass read- ings off the rotating mirror that is mounted on the gyro’s axis this is busying me right now, as Schuler has to keep away from any kind of research for a longer period, for health reasons. It would be fine and nice if you came with your wife to see us how about around July 6th? July 8th is anyway the 2nd date scheduled before the Regional Court of Appeal  your presence then would surely have a clarifying and at the same time intimidating effect for the other side in this matter, you simply are the bogeyman. And by then I shall surely be able to demonstrate the rubber to you, which is made conductive on the surface with carbon I think it works. Today we are all weighed down by Rathenau’s murder  I was reminded that you knew him well and prized him very much how very far extremely exaggerated nationalistic sentiment leads people away from any sense of goodness!