DOCS.

7

&

8

79

Doc. 7

Review

of

A.

FLIEGNER,

"On

Clausius's

Law

of

Entropy"

("Über den

Clausius'schen

Entropiesatz,"

Naturforschende

Gesellschaft in

Zürich.

Vierteljahrsschrift

48

(1903):

1-48)

[Beiblätter

zu

den

Annalen

der

Physik 29

(1905):

236]

The

author examines

the

entropy

changes

of

a

system

during

a

process

presumed

to

be

strictly discontinuous

(discontinuous expansion

of

a

fluid)

and

concludes

from

his

calculations that the

entropy

decreases

at

the

beginning

of

the

sudden expansion.

Considerations

concerning

irreversible chemical

processes

lead the author

to

the conclusion that

the

equation

dQ/T

dS

holds

only

for exothermic but

not

for

endothermic

processes.

Similarly,

the

equation

is

not

supposed

to

hold for

cooling

mixtures. It is therefore

understandable

that the author closes with the

following

sentence: "Thus,

the

question

of

whether

the

entropy

of the universe

does

change

at

all,

and

if it

does, then in

which

sense,

cannot yet

be

answered

at

all

at present, and

will

probably

remain

undecided

forever."

[1]

Doc.

8

Review of

W.

McFadden

ORR,

"On

Clausius'

Theorem

for Irreversible

Cycles,

and

on

the Increase

of

Entropy"

(Philosophical

Magazine

and Journal

of

Science

8

(Series

6)

(1904): 509-527)

[Beiblatter

zu

den

Annalen

der

Physik 29

(1905):

237]

The

author

shows

that in the

Vorlesungen

über

Thermodynamik

[Treatise

on

Thermodynamics]

Planck

applies

the

concepts

"reversible"

and

"irreversible" in

[1]

a

sense

somewhat

different

from

that in

which he

defines

them.

Then he

advances

a

series of objections that

may

be

raised

against

various

ways

of

[2]

representing

the foundations

of

thermodynamics;

especially

noteworthy

among

these objections is

that

by

Bertrand,

i.e., that the

pressure,

temperature,

[3]

and

entropy

are

defined

only

for the

case

that

at

least sufficiently small