1 8 4 D O C U M E N T 2 9 8 N O V E M B E R 1 9 2 1
Ehrenfest’s house is very full of fun from the children and the two
But I am still looking forward to home. I’m just a bit afraid of the deluge of mail.
I hope Ilse straightens out her relations with Dr. S[teinthal] again, otherwise I
myself will give it a try when I’m back in
Kisses to all three of you from your
Poor unfortunate me. All of you should wrap her up
in a veil when I come home.
297. From Paul Winteler
[Zurich, 12 November 1921]
[Not selected for translation.]
298. From Hendrik A. Lorentz
Haarlem, 13 November 1921
These last few days I have been continuing to think about your experiment with
the luminescent canal-ray particles (bending? of the light
and about the
considerations that led you to it. I now encounter a problem in these considerations,
although your basic idea itself appeals to me very much. Allow me to discuss it
briefly with you.
[Probably not exactly as you had conceived it; in part involuntarily
changed by me. What I say surely does not stray far from Ehrenfest’s remarks.]
Upon the emission of light there are two sorts of radiation. They are:
1. An interference radiation, which occurs according to the normal laws of optics
but does not transmit any energy. One can, for inst., imagine that this radiation is
composed of normal electromagnetic oscillations but of vanishingly small ampli-
tudes. Consequently, they themselves cannot be observed; they just show the way
for the energetic radiation. It is like a dead pattern that only comes to life through
the energetic radiation.
2. The energetic radiation. It is composed of indivisible quanta of the quantity
h . Their path is given by the (vanishingly small) flow of energy from the interfer-
ence radiation and therefore they can never reach a spot where this flow is zero
(dark interference fringes).