22
DOC.
31
JULY
1905
31.
Expert Opinion
by
Alfred
Kleiner and Heinrich
Burkhardt
on
Einstein's
Dissertation[1]
[Zurich,
22-23
July
1905][2]
Institute of
Physics
University
of Zurich
Rämistr.
69
Prof. Dr. A.
Kleiner
Expert Opinion
on
Mr.
Einstein's
application
for the
conferment of
a
doctoral
degree.
Mr.
Einstein, who has
become
well known
on
account of
several
noteworthy papers
in the
area
of mathematical
physics (spec.,
molecular
theoret.),[3]
has
submitted
a
dissertation under the
title
"A New
Determination of
Molecular Dimensions."[4]
He
seeks
to
solve
the
problem,
which he
selected
and
posed
to
himself,
by calculating
observable
physical
constants
from the
immediate
properties
of
molecules,
their
dimensions,
and their numbers
per
unit
volume.
Among
the
physical
constants
of
this
kind,
he finds
the
viscosity
of
undissociated solutions and
the
diffusion coefficients to be
suitable
for
his
purpose,
since
these
two
depend
in
a
different
way on
the
dimensions
and the
number of the
dissolved
molecules,
so
that
it becomes
possible
to
determine
both
of
these
two
quantities separately
on
the
basis
of observational data.
The main
problem
that had
to
be solved
was
the
mathematical determination of
the
difference
between
the
viscosity
of
a
solution
and
that of
the
solvent; to
make
the
calculation
possible,
it
is
necessary
to
make
a
few artificial
assumptions
(spherical shape
of
the
molecule)
that
may
seem
admissible,
since it
is
only
the order of
magnitude
of
the
dimensions
sought
that
can possibly
be
determined. The
arguments
and
calculations
to
be carried
out
are
among
the
more
difficult
ones
in
hydrodynamics,
and
only
a
person
possessing perspicacity
and
training
in the
handling
of
mathematical and
physical
problems
could
dare
to
tackle them, and it
seems
to
me
that
Mr.
Einstein
has
proved
that
he
is
capable
of
working successfully on
scientific
problems;
I
would
therefore
recommend that the dissertation
be
accepted.
Since
the
main
achievement of
Einstein's
thesis consists
in
the
handling
of
differential
equations,
and
hence
is
mathematical
in
character
and
belongs
in
the domain
of
analytical
mechanics,
I would like to ask the
dean
also
to
approach
my colleague,
Professor
Burkhardt,
for
an
expert
opinion.
A.
Kleiner
At
the
request
of
my
colleague,
Professor
Kleiner, I
reviewed
the
dissertation
of
Mr.
Einstein,
and checked the
most
important part
of
his
calculations,
that
is,
all
of
the
places
indicated
by
Professor
Kleiner.
What
I
checked,
I found
to
be correct
without