sci3.001.30-ms-03

Kerr Walter obtained the first effect, the absorption edge, but not the
lines. In order to prove whether this effect accounts quantitatively for
the results of Duane's experiments different ways can be used.
Experimentally the directions of the observation that the beam moves
with the crystal beyond the position at which reflection of the
same ray occurs from outside can be established. Since such
reflections should appear for all planes for all possible order it
seems improbable that they exist, since they havent been found
previously. Of course for the usual crystals NaCl, CaCO₃ or sugar
the heaviest atoms have such long characteristic rays that
they wouldn't be reflected [(Lambda is greater than 2 delta)] or would permit only a
narrow bundle. For Zn in ZnS or I in KI an
extensive array of such reflection would be possible, and could be
shown for these substances if the intensity were sufficient to stand
out on top of the white radiation and produce the [alpha- wast] of Clark-
Duane's curve. Since it deviates from the ordinary reflection
law the question rises as to whether we haven't a trace of these
reflections in the "X peaks" of these authors, since indeed these
vanish at the excitation limit of characteristic radiation.
The author doesn't believe this, for the direction relations of this
peak cant according to the description be brought into agreement
with the expected properties of the reflections considered.
It is to be desired next that these phenomena be further
substantiated.

So if now out ofthe whole observation appears to give nothing definite leading
beyond the sphere of previously known phenomena, still it
cant be said that no interest accompanies an exact as
possible quantitative verification of the effect of an absorption edge in the
crystal, which is the chief part of these experiments. Our calculations
assume that the absorption edge comes completely into play, not
bearing in mind considering accordingly that at this angle an
especial "absorp extinction-coefficient" comes into play,
according to Darwins' in an ideal crystal this far exceeds the
normal absorption coefficient;
{Darwin Phil Mag 27, 315 & 675, (1914)
Bragg, Jams & Bozanquist, Phil Mag March & July 1921}
the ray should be entirely absorbed at the correct angle
at a depth at which only a slight weakening would occur from
the normal absorption. Since this "extinction" goes back to
interference, and accordingly to radiation, there is no reason