272 THEORY OF RELATIVITY
Wahrscheinlichkeit
zu,
weil ihre die Maße des
bewegten
Elektrons betreffenden
Grundannahmen
nicht nahe
gelegt
werden durch theoretische
Systeme,
welche
größere Komplexe von Erscheinungen
umfassen.[122]
This cautious attitude toward
Kaufmann's
results
proved justified. During
the
following
years,
controversies
over
the
interpretation
of
the
experimental
results
prevented
investi-
gations
of
this
topic
from
playing a
decisive role in
contemporary
evaluations
of
the
theory
of
relativity.[123]
Bestelmeyer
carried out
ß-ray
experiments generally
regarded
as
incon-
clusive, while
Bucherer's
results
favoring
the Lorentz-Einstein
equations were seriously
questioned.[124]
Experiments using
cathode
rays, reported by
several
investigators starting
in
1910,
proved similarly
inconclusive. Almost
a
decade
elapsed
until
generally
accepted
data
on
the variation
of
electron
mass
with
velocity were
at
hand;
these data
supported
the
relativistic
predictions.[125]
In
1907,
Einstein
agreed
to
write
a
review article
on relativity
for Johannes Stark's
Jahrbuch der
Radioaktivität und
Elektronik.[126]
He indicated what he had read
on
the
subject by
this time:
Besides
my
own,
I
know
of
a
paper
by
H. A. Lorentz
(1904),[127]
one
by
E.
Kohn,[128]
one
by
Mosengeil,[129]
as
well
as
two
by
Planck.[130]
I
am
not fa-
miliar
with other relevant theoretical
papers.[131]
Ausser
meinen
eigenen
Arbeiten ist
mir
eine Arbeit
von
H. A. Lorentz (1904),
eine
von
E.
Kohn,
eine
von
Mosengeil
sowie zwei
von
Planck bekannt. Andere
die
Sache betreffende theoretische Arbeiten sind mir nicht
bekannt
geworden.
Einstein indicated the
care
he had taken to make the review
pedagogically
useful:
I
have taken
great pains
to
clarify
the
assumptions
employed,
by-as
far
as
possible-introducing
these
assumptions one by one
and
pursuing
their
conse-
quences
in
sequence.
An die
Klarlegung
der benutzten Annahmen habe ich viel
Sorgfalt
verwendet,
[122]
Einstein
1907j (Doc. 47),
p.
439. For
an
earlier statement
of Einstein's
attitude toward
the
unifying
power
of
theories,
see
Einstein
to
Marcel
Grossmann, 14
April
1901
(Vol. 1,
Doc.
100).
[123]
For reviews
of
the
early experiments on
the variation
of
the
mass
of
the electron with its
velocity, see
Laub
1910;
Laue
1911b,
pp.
16-
18;
Guye
and
Lavanchy 1916,
pp.
288-292;
Pauli
1921, p. 636;
and Lorentz
1922, chap.
VII.
[124]
Einstein
corresponded
with Bucherer in
1908,
shortly
after the latter carried out his
ex-
periments.
[125]
See
Guye
and
Lavanchy
1916,
and
Glitscher
1917.
[126]
Einstein
to
Johannes
Stark,
25
September
1907. See also
note
47.
[127]
Lorentz 1904a.
[128]
That
is,
Emil
Cohn.
See Cohn
1900,
1902,
1904a,
and 1904b. A
copy
of
Cohn 1904a
is
in Einstein's
collection
of
reprints, now
in
IsReW.
See
also note 27.
[129] Mosengeil
1907.
[130]
Presumably a
reference to
Planck
1906a,
1907a. Einstein did not
yet
know
of Planck
1906b,
1907b
(see
note
121).
[131]
Einstein to Johannes
Stark,
25
September
1907. In his
reply (Stark
to
Einstein,
4 October
1907),
Stark cited
Planck
1907a,
Laue
1907.
Stark
later
told Einstein
about
Planck's
studies
of Kaufmann's
experiments.