258
DOC. 354
FEBRUARY
1912
reflective
cap.
empirical curve
according
to
Rubens
Obviously,
the
absorption
intervenes
here,
which
cannot
be
properly
taken
into
account
simply by using
a
"friction
term" that
is proportional
to
the
velocity.
Rubens
wrote
that the
absorption
decreases
sharply
with
decreasing temperature.
It
is
therefore
to be
expected
that the
curve
will
go over
into
the theoretical
curve
at
very
low
temperatures.
I
wrote
this
to
Rubens. He
has
probably already set out to
do
the
experiment.
There
cannot
possibly
be
two
proper frequencies.
I
proved
in
my
last
paper
(in
a
thermodynamical
way)
that the radiant
energy
Nhv
is always
required
for
the
absorption
of
the
photochemical decomposition
of
one gram-molecule
by
Wien's
light.[6]
This
can
be
deduced
from the radiation formula
and the law
of
mass
action. So
one
does not
need
the
quantum
hypothesis
for this.
Yesterday
I received
a
letter
from
Warburg,
to
whom
I
related
this
matter in
Brussels,
and he writes
that
he
found the law
exactly
confirmed
in
one
substance.[7]
Abraham
has
worked
out the
new
gravitation
theory
somewhat
further;
we are
corresponding
about
this because
we are
not
exactly
of
the
same opinion.[8]
An
astronomer from
Berlin
is
working
hard
on
the verification of the
bending
of
light rays
at the
sun.
He
has all
photographs
of solar
eclipses
sent to
him
&
he
measures
them.[9]
The
most
important improvement
that Habicht
has
made
in
the
Maschinchen consists
in the
gold-plating
of
the first
stages.[10]
I have
surely
written
to
you
already
about
the
success
he
had
with it in
Berlin.[11]
The
folks
were
breathless.
My
appointment
to
Zurich
(the
Polytechnic)
arrived
a
few
days
ago.[12]
So
we
will
be
moving
at
the end of
July.
You
must
come
to
see me
either here before that
date,
or
there after
it,
but best
cum
familia.
Do
write
soon again
to
your
Albert
Best
regards to
Anna
&
Vero.
[...][13]