DOC. 12 THERMODYNAMIC
DEDUCTION
293
Published
in
Journal de
physique 3
(1913):
277-282. Lecture delivered
at
a
meeting
of the
Societe
francaise
de
physique,
Paris, 27
March
1913, published
April
1913.
[1]This
paper
summarizes results earlier derived
in
Einstein
1912b
(Doc. 2)
and
Einstein
1912f
(Doc.
5). In
a
contemporary
letter Einstein
wrote:
"Tomorrow
I must
go
to Paris
to give
a
lecture
in
French
at the
Sorbonne. Isn't that
daring?
Keep
your
fingers
crossed
on
Thursday
morning,
because then
the
miracle
will
take
place" ("Morgen
muss
ich
nach
Paris,
um
in
der
Sorbonne einen französischen
Vortrag
zu
halten.
Ist das
nicht kühn? Halte mir
also
am
Don-
nerstag Vormittag
freundlich den
Daumen;
denn dann
wird das
Mirakel stattfinden."
See Ein-
stein
to
Elsa
Löwenthal, 23
March
1913
[Vol. 5,
Doc.
434]).
For Einstein's
happy
memories
of his
trip
to Paris,
see
Einstein
to
Marie
Curie,
3 April
1913
(Vol. 5,
Doc. 435), and
Einstein
to
Jean
Perrin, 4
April
1913
(Vol. 5,
Doc. 437).
[2]See
Einstein 1905i
(Vol.
2,
Doc.
14), §9,
for Einstein's
first
application
of
the
quantum
hypothesis
to
photochemical processes.
See the
editorial
note,
"Einstein
on
the
Law of
Pho-
tochemical
Equivalence,"
pp.
109-113,
for
a
brief review of Einstein's work
on
photochemistry.
[3]In
Einstein 1912b
(Doc.
2) only an
infinitely
small
frequency
domain
was
assumed
to be
photochemically
effective; in
Einstein
1912f
(Doc. 5)
Einstein
generalized
his
approach to
a
finite
frequency
range.
[4]The
first,
the second,
and
the
fourth of
the
following
five
assumptions are explicitly
stated
in
Einstein 1912b
(Doc. 2), pp.
833-834; the
others
are
implicitly
assumed.
[5]See
Einstein
1912b
(Doc. 2), pp.
834-844, and, in
particular,
Einstein
1912f
(Doc. 5),
pp.
882-884,
for
Einstein's earlier discussion of what
he
there called
"improper"
("außergewöhnliches") thermodynamic equilibrium.
[6]Einstein had earlier denoted
the
energy
absorbed
by a
mole
as
Ne
(see
Einstein 1912b
[Doc. 2], p. 835).
[7]The numerator
on
the
right-hand
side
of
the
equation
should
be
p.
[8]Equation
(c)
is the
equation
in the
preceding
line.
[9]"l'equation
(2)"
should
be
"l'hypothese
2°."
[10]See
Einstein 1905i
(Vol.
2,
Doc.
14),
§9,
and Stark
1908a,
p.
893; see
also Stark
1912
for Stark's claim
to
priority
on
this derivation, and
Einstein
1912g
(Doc. 6)
for Einstein's
response.
[11]This
was
earlier established
in
Einstein
1912f
(Doc. 5).
[12]For
a
brief discussion of
subsequent experimental
work
on
the law
of
photochemical
equivalence
and Einstein's continued interest
in the matter,
see
the
editorial
note,
"Einstein
on
the
Law of Photochemical
Equivalence,"
pp.
112-113.