D O C U M E N T 5 0 9 A P R I L 1 9 2 7 5 0 5 an apparent resistance, which is vanishingly small compared to ohmic resistance. It’s different with a coil. Here, however, the great magnetic resistance of the air gap is decisive and the unavoidable great ohmic resistance of the windings and espe- cially of the tube. I believe that there is nothing special for you to look for there. The greatest improvement of recent times consists in that, instead of a small membrane in conjunction with a horn, a large, very light, functionally strong and non-clamped plate is used, and, actually, without an acoustic horn. I’m leaving tomorrow with Tete[3] to go into the countryside a bit for a week. He has a sore throat. Hopefully, it will clear up soon. We’ve already played a lot of mu- sic. Particularly nice is a concerto by Tartini.[4] Best regards, your Papa Regards from Tete. He’ll write you later. He’ll also send you the sweater. 509. Verse for Margot Einstein [Kapellensee, 8 April 1927] This retreat[1] is not half bad where I am dwelling with my son[2] Delightful for you would this also be Were it not for your delicate stomach Daily through forest and meadow The lazy creature trudges. If one had always just been lazy, How should the spirit recover there? Before I go to bed, in conclusion, I send you a fatherly greeting. Your Albert Greetings to Rudilse.[3]