006 
common side of the two cubes come together end to end, there will 
be produced, by pure gravitation, a force of attraction between them 
which may be of any amount, however great, and which will be 
greater, the greater the ratio of the w'hole space unoccupied within 
the boundary of either cube, to the space occupied by the matter of 
the bars. . 
This illustration has been chosen merely for the sake of definite - 
ness and simplicity ; but it is clear that any arrangement, however 
complex, of woven fibrous structure, provided only the ratio of the 
unoccupied to the occupied space is sufficiently great, will lead to the 
same general conclusion. Farther, it is clear that the same result 
would be produced by any sufficiently intense heterogeneousness of 
structure whatever, provided only some appreciable proportion of 
the whole mass is so condensed in a continuous space in the interior 
that it is possible, from any point of this space as centre, to describe 
a spherical surface which shall contain a very much greater amount 
of matter than the proportion of the whole matter of the body 
which would correspond to its volume. Except in imposing this 
condition, the theory now suggested interferes with no molecular 
hypothesis hitherto propounded, continuous or atomic, finite atoms? 
or centres of force, static or kinetic. 
Physical science abounds with evidence that there is an ultimate 
very intense heterogeneousness in the constitution of matter. All 
that is valid of the unfortunately so-called “ atomic” theory of 
chemistry seems to be an assumption of such heterogeneousness in 
explaining the combination of substances. This alone, it is true, 
does not explain the law' of definite combining proportions ; but 
neither does the hypothesis of infinitely strong finite pieces of 
matter ; and whatever is assumed to be the structural character of 
a chemical compound, a dynamical law of affinity between the two 
substances, according to the proportions of them lying or moving 
beside one another, must be added to do what some writers seem to 
suppose done by their “ atomic theory.” 
It is satisfactory to find that, so far as cohesion is concerned, no 
other force than that of gravitation need be assumed. 
The following Donations to the Library were announced : — 
On Binocular Vision and the Stereoscope : a Lecture by William 
B. Carpenter, M.D., &c. 12mo. — From the Author. 
