DOCS.
367,
368
AUGUST
1917
363
possibly
can
be
lacking.
Albert returned
to
Zurich
yesterday
in accordance with
Miza’s wish.
He
has
developed
well
but
often behaves
a
bit
roughly
toward
me
out
of
ingrained
habit. Paul
got along very
well
with him and climbed
the
Schwalmis with him
on Sunday.
I
happened
to
meet
Stocker
(Patent
Office)
here;
we
reminisced[2]
and
were
pleased
to
see
each other. When
is Vero
coming?
We
would all be
very glad
to
see
him.
I
shall
try
to meet Mrs. Adler before
I
travel
to
Berlin;
thank
you
for
your help
in
the
matter.[3]
I
haven’t been
getting
much
studying
done.
I have
some
worthwhile
things
here
by
Levi-Civita
on
gravitation.[4]
He is
also interested in
the
À
term.[5] I
find
the
papers
on
the
foundations
of
crystallography,
which Schoenflies sent
me
at
my request,
not
particularly
clear.[6]
Where
in the
countryside
are
you going
and for how
long?
I
would
like
to know because of
my
Zurich
stop
at
the
end
of
my stay.
Warm
regards
to all
three
of
you,
yours,
Albert.
368. To
Tullio Levi-Civita
Lucerne, 2
August 1917
Dear
Colleague,
I
shall make
use
of
this
holiday
trip to
my
homeland
to
send
you
direct
greet-
ings,
for
once.[1]
I
recently
discovered
your
fine
new papers
at
Hurwitz’s[2]
and
immediately
took them
along
in order
to study
them here
at leisure.[3] I
admire
the
elegance
of
your
method
of
calculation. It must be nice
to
ride these fields
on
the
cob
of
mathematics
proper,
while
the
likes
of
us
must
trudge
along
on
foot.
It
pleased
me
especially
that
you
have
graciously accepted
the
new
A
term,[4]
without
which
it
does not
seem
possible
to form
an
actually
relativist notion
of
the
world
as a
whole.
It
is true
that
nature
may
also have chosen
an entirely
different
path;
this
one
is just mathematically
the
simplest
conceivable. Stellar
statistics has
not
legitimized
it
yet,
though.[5]
Your
objections
to
my
interpretation of
the
energy components
for
the
gravi-
tational
field
still do not make
sense
to
me.
I
would
like to repeat
what
lets
me
cling
to
my
reading.[6]
1)
I
proceed
from
a
Galilean
space,
that
is, one
with
guv
constant.
Through
a
simple change
of frame of reference
(introduction
of
an
accelerated reference
system
K'),
I
then
arrive at
a
gravitational field.
If
a
pendulum
clock,
driven
by a weight,
is
installed at rest in
K',
this
gravitational
energy
is
converted
into
heat,
whereas
a
gravitational
field, or
in
other
words,
gravitational field