516
DOC.
495
MARCH
1918
495.
From Friedrich Kottler
Vienna,
30
March
1918
Esteemed
Professor,
I would
like
to extend
my
sincere
thanks
for
the
mailing
of
your paper
and
for
your
k[ind]
letter.
Much
to
my
regret
did
I learn of
your
illness.[1]
Please
accept
my
best
wishes for
a
speedy recovery
and do let
me
know
on
occasion how
your
state of
health
is.
Allow
me now
to return
to
the
subject
of
my
paper.[2]
First
of
all,
I
would like
to
state,
in order
to
avoid
misunderstandings:
For
the
case
that
my exposition
should
prompt
you
to
a reply,
I
merely
made
the
request
that
a
discussion
by
letter
precede
it. Thus
not,
for
instance,
that
a
public reply
not
take
place
at
all,
insofar
as
you
deem
it
necessary,
of
course.
I
would
like
to
hope
that
your describing my
presentation
as
hard
to
un-
derstand this
time
as
well
was
simply
a
first
impression upon cursory
perusal.
Permit
me
to
reiterate
again
the
request
for
patience
to
the reader
made in
the
introduction.
In
addressing
the
individual
objections,
I
allow
myself
the
following
rebuttals:
1)
My guiding hypothesis
is:
g
=
-c2
in
Cartesian
coordinates.[3] These
are
coordinates for
which[4]
gik
-
¿ík
“I-
khiK
(¿11 =
¿22 = ¿33 =
1, ¿44
=
-c2,
¿t«
=
o
i^K,
k
=
6
•
7
•
l(r8gr_1cm3sec_2.)
It states
clearly:
All solutions
that
permit
only
a
single
description
in
Cartesian coordinates
for which
g
^
-c2
are
inadmissible.
If
there
are
several
descriptions
in
Cartesian
coordinates,
then
only
the
coor-
dinate
system
for which
g
-
-c2
is
admissible.
As
an
example
of the
latter, I
mention
the
homogeneous
field
(acceleration
7),
s[ee]
§37
of
my
paper:[5]
-ds2
=
fc2
+
if
+
(l
+
ái2.
'
r2
a) According
to
the
equivalency
hypothesis:[6]
-ds2
=
dx2
-I-
dy2
+
dz2
-
c2
^1
+ dt2.
b)
According
to
gravitation
theory:[7]