Volumes of Salt- Solutions. 131 
&c. of sodium and potassium, the apparent isomorphism is the 
result, not of the isomorphism of the molecules themselves, 
but of the mutual relations of the molecules and intermolecular 
spaces being such as to produce the same crystalline form. 
Id conclusion, I may be allowed to point out that this 
method of investigating the molecular volumes of salts is, in 
all probability, capable of extension to organic substances ; 
and that, by comparing solutions of various organic bodies 
which differ by one or more CH 2 -groups, or in other respects, 
it maybe possible to determine the volume of these differences. 
Such solutions need not necessarily be aqueous. At present, 
I have made only a few experiments in this direction ; these 
were with formiate, acetate, and butyrate of sodium ; the 
results are given in Table IX. Analysis showed that, while 
the formiate and acetate of sodium were pure, the butyrate 
contained 21*7 p. c. of sodium, theory requiring 20'9 p. c. 
All attempts to purify the small quantity at my disposal were 
vain ; the impurity was probably acetate ; this would tend 
to reduce the molecular volume by increasing the specific 
gravity. 
Table IX. 
X. 
Salt. 
t°. 
S. 
Mol. vol. 
Diff. per 
CH 2 . 
2-0 
2-0 
20 
10 
1-0 
10 
2-0 
2-0 
20 
10 
1-0 
1-0 
o 
20 
20 
20 
20 
20 
20 
40 
40 
40 
40 
40 
40 
1-04349 
1-04380 
1-04561 
1-02278 
1-02280 
102345 
104173 
1-04279 
104436 
1-02184 
1-02218 
1-02276 
1935-82 
1881-58 
1851-58 
186746 
1840-05 
1825-19 
1939-08 
1883-41 
1853-82 
1869-18 
1841-16 
1826-44 
13-74 
15-00 
13-70 
14-86 
13-92 
14-81 
14-07 
14-72 
I hope soon to be able to carry out further experiments in 
the field of inquiry thus opened up. 
