122
MOLECULAR
DIMENSIONS
We
will
carry
out
the calculation for
an
aqueous
solution of
sugar.
From
the
data
on
the
internal friction
of
the
sugar
solution cited earlier, it
follows that for
20°C
NP3
=
200
.
According
to
experiments
of
Graham
(calculated
by
Stefan), the
[60]
coefficient of diffusion
of sugar
in
water
is 0.384 at 9.5°C,
if
the
day
is
[61]
chosen
as
the unit
of
time.
The
viscosity of water at 9.5°
is 0.0135.
We
will insert
these data in
our
formula for the coefficient
of
diffusion,
even
though
they
have been
obtained
using
10%
solutions,
and
a
strict validity
of
our
formula
cannot be expected
at such
high
concentrations.
We
obtain
Neglecting
the differences
between
the values
of P
at
9.5° and 20°,
the values
found
for
NP3
and
NP
yield
[59]
NP
=
2.08.1016
.
[62]
P
=
9.9
x
10-8
cm
,
N
=
2.1
x
1023
.
The
value
found
for
N shows
satisfactory
agreement
in its order
of
[63]
magnitude
with values
found
for this
quantity
by
other
methods.
Bern,
30 April
1905.