THEORY OF
RELATIVITY
267
The attention that this
theory so quickly
received
from
colleagues
is
surely
to be
ascribed
in
large part
to the resoluteness and warmth
with which he
intervened
for this
theory.
Der Entschiedenheit und
Wärme,
mit der
er
für
diese
Theorie
eingetreten
ist, ist
wohl
zum großen
Teil die
Beachtung
zuzuschreiben,
die diese
Theorie
bei den
Fachgenossen so
schnell
gefunden
hat.[78]
Other
physicists
also started to discuss
Einstein's
work in
1905
and 1906. Two months
after it
appeared,
Kaufmann cited it in
a preliminary report
of
his recent
experiments on
the
mass
of
electrons in
ß-rays.[79]
The
following year,
in
a
fuller
discussion of
his results,
while
noting
that the two theories
yield
the
same equations
of
motion
for the electron, he
gave
the first
clear
account
of
the basic theoretical difference between
Lorentz's
and Ein-
stein's
views.[80] Drude,
the editor
of
the
Annalen,
cited
Einstein's
paper
in the second
edition
of
his standard text
on
optics,[81]
as
well
as
in his article
on optics
in
the
Handbuch
der
Physik.[82]
Röntgen
wrote to Einstein
asking
for
copies
of
his
papers on electrodynam-
ics,[83] presumably
in connection with
a
talk
Röntgen was
to
give on
the
equations
of
motion
of
the
electron.[84] Sommerfeld,
who heard the
talk,
soon
read
Einstein's
work and
was so impressed
that he decided to
give a colloquium on it.[85] During
1907,
Einstein
was
in
correspondence
about the
theory
with
Planck,
Laue,
Wien,[86]
and Minkowski.[87] In the
same
year,
he
was
asked
to
write
a
review article
on relativity,
which
appeared
in
Stark's
Jahrbuch der Radioaktivität
at the end
of
the
year,[88]
and
a major publishing
house in-
quired
about the
possibility
of
a
book
on
his
research.[89] A
reference
by
Ehrenfest in 1907
to
Einstein's
theory
as a
"closed
system" ("abgeschlossenes
System")[90]
led Einstein to
clarify
his view
of the
nature
of
the
theory.[91]
By
1908,
the
theory
of
relativity, though
[78]
Einstein
1913,
p.
1079.
[79]
See
Kaufmann
1905.
[80]
See
Kaufmann
1906a,
pp.
491-493.
See
also
Kaufmann
1906b,
which contrasts
Cohn's
theory
to
those
of
Lorentz and Einstein.
[81]
See
Drude
1906a, p.
467.
[82]
See Drude
1906b, p.
1387.
[83]
See Wilhelm
Röntgen
to Einstein, 18
Sep-
tember
1906.
[84]
The talk
is
discussed in
a
letter
of
Arnold
Sommerfeld
to
Wilhelm
Wien,
23 November
1906
(GyMDM,
Wien
Nachlaß,
Mappe
Som-
merfeld).
[85]
See Arnold Sommerfeld to Wilhelm
Wien,
23 November 1906
(GyMDM,
Wien
Nachlaß,
Mappe
Sommerfeld).
The letter
indi-
cates
that Wien had
previously
commented
to
Sommerfeld
on
Einstein's
paper. By early
1908,
Sommerfeld
was corresponding
with Einstein
(see
Eckert and Pricha
1984).
During
the winter
semester
of
1908-1909 Sommerfeld
gave a
course on
the
theory
of
relativity
at
the Univer-
sity
of
Munich,
which he believed
to
be the first
such
course (see Jungnickel
and
McCormmach
1986b,
p.
283).
[86]
Einstein had
a lengthy correspondence
with Wien
on
the
question
of whether
superlu-
minal
signal
velocities
are compatible
with
Maxwell's
theory.
See Vol.
5,
the editorial
note,
"Einstein
on Superluminal Signal
Velocities."
[87]
Minkowski
wrote
Einstein
to
request a
copy
of
his
paper,
for discussion
at
a Göttingen
seminar
(see
Hermann Minkowski
to Einstein, 9
October
1907).
The seminar
on electrodynamics
during
the 1907 winter
semester
was
conducted
by
Hilbert
and Minkowski
(see Pyenson 1985,
p. 83).
[88]
For
correspondence
with Stark about this
review,
see
Hermann
1966. For
Einstein's
re-
view
paper, see
Einstein
1907j
(Doc. 47).
The
paper
is
discussed below in
§
V.
[89]
See B. G. Teubner
to Einstein,
3
October
1907.
[90] Ehrenfest
1907.
[91]
See Einstein
1907g (Doc. 44).
For
a
dis-
cussion
of
this
paper, see
§
V
below.