64
DOCS.
91,
92
MARCH
1908
arrived,
in
a
way,
at
a
proof
of
the contraction
hypothesis by
postulating
the
proposition
that
a
joint
translational motion
is not perceivable
by
a
comoving
observer." It
seems
to
me
that,
in
a way,
Hasenöhrl,
too,
actually
presupposes
the
relativity
principle through
his
postulate,
and
by applying
the
Maxwell-Lorentz
eqns.,
he
arrives,
of
course,
at
the
"contraction
hypothesis,"
which,
after
all,
also
follows for
you as a
necessary
conse-
quence
of the
two principles
(const.
of
the vel.
of
light
and
relativity
pr.).-
I would be
very
grateful
if
you
could send
me
your
papers
(1)
"Uber
die
von
Relevitätspr. geforderte
Trägheit
der
Energie"
["On
the
Inertia of
Energy Required by
the
Relativity Principle"],[6] (which
unfortunately
escaped my
notice)
(2)
the
paper
in
which
you apply
Planck's
radiation
theory
to
photoelectric
processes.[7]
Thanking
you very much,
I
remain
respectfully yours,
J. Laub
92.
From
Adolf
Gasser
[Winterthur,]
9
March 1908
My
dear
Einstein,
That's what
I
call
a
nice
surprise
for
us!
While
we
here
naively
believed
that
we
might
help
you secure a
teaching
position, you
already
had the
professorship
in
your
pocket.[1]
Our heartiest
congratulations
on
your
deserved
success!
It
is
of
course
of
enormous
interest
to
us
to
hear
how
you suddenly
came by
these
connections;
we
hope
to
hear
more
about
it
later. Does
your
discretion
apply
to
the location
as
well?
Because
most
of
all
we
wonder where
you
will be
going.
Is it
perhaps
Zurich? That
would be
perfect.
Permit
me
to
make
a
small
remark.
Since
I
know
you
as a
trusting
soul who
is not
as
well
acquainted
with the
"real
forces
of harsh
reality" as
with
the
physical
laws
of
unspoiled nature,
it
might
not
be
out
of
place
to
warn you
to be
cautious and
to
examine
thoroughly everything and,
most
of
all,
to
find
out
whether
your protector
possesses not
only good
will
but the
necessary
power
too.[2]
Furthermore,
may
I
remind
you
that
you
stated
some
time
ago
that
you
would
prefer
a
post
at
a high
school to
a
professorship.
You know
that
I
think
differently,
and
that
my
unqualified
advice
is
that
you
should
accept
the
professorship;
but
if
you
still
stand
by your
earlier
position,
you
can
nevertheless
apply
here. It
would be
kept confidential,
so
that
you
would not risk
anything.
You
will notice
that
I
am
speaking
here somewhat
pro domo,
since I would
love
to
have
you
with
me,
but
this will
certainly
not influence
you
in
any way.
The
closing
remark of
your
letter makes
me
think that
you
have not
received
our
last 2
letters,
which
we
sent to
your
address about the
middle
of
January
in
reply
to
your
wife's
letter.[3]
By
way
of
orientation,
let
me
mention that the letters contained
the