562 DOCS.

543,

544 MAY

1918

543. To Felix Klein

[Berlin,

19

May

1918]

Esteemed

Colleague,

I shall be

glad

to send

you my

recent

published

notes.[1]

On

Thursday I

sub-

mitted

a fairly

extensive

exposition

of

my

views

on

the

energy

law.[2]

I shall send

you

the

correction

proofs,

which

I

am

probably going

to be

receiving

in

a

few

days.

I

was

very sorry

that

I

could

not

attend the

lectures of

my

dear

colleague

Planck.[3]

My

doctor

has forbidden

me

all those

sorts of

things, unfortunately.[4]

I

shall be

glad

to

register myself

with

the

German Mathematicians

Association,

as

you

consider

it

appropriate.[5]

With

amicable

regards, yours truly,

A. Einstein.

Recipient’s

note:

“Now

the entire

Levi-Civita

material.

Should I

write

a

note

on

hypothesis

B?”

544. From Hermann

Weyl

Zurich,

20

Schmelzberg St.,

19

May

1918

Dear

Colleague,

With

my

“correction” of sheet

15,

I

really

have

blundered![1]

Although

the

statement at

the

top

of

p.

226 correct:

on

the

sphere,

h

is

an

odd function

of

x4

=

z,

just

as

in

the

fluid

cap case,

eq.

(66),

h =

b0/z.[2]

What

I

had

incomprehensibly

overlooked,

however,

is

this:

that the

boundary

condition of

vanishing pressure

on

both latitudinal

spheres

does

not

require

the

same

value for h but

rather the

same

value for

ƒ.[3] Now,

the

equation

for

A:[4]

(*)

dA

*=7fcrv,,

yields

the

solution

A,

which

is

an

odd

function of

z;

hence

the

corresponding ƒ

=

A/h

is

even.

Because

of

the

arbitrary

additive constant in

the

solution of

(*), ƒ can

also be

replaced by

ƒ+

const./h.

If

on

both

boundary

spheres

r

=

r0,

symmetrical

to

the

equator,

ƒ

must

assume

the

same

value

f0

=

v/u0 ,

then

this

const.

=

0