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