264 Prof. Whewell’s Demonstration 
this hypothesis, per se, any matter must be imponderable ; being 
endowed with a property the very opposite of attraction of 
gravitation. This last mentioned property exists between masses 
consisting of both kinds of particles, so far as the attraction 
between the heterogeneous atoms predominates over the repul- 
sion between those which are homogeneous. It would follow 
from these premises, that all matter is ponderable or otherwise, 
accordingly as it may be situat 
22. Can the ether by which, neichciiad to the undulatory theory, 
light is transmitted, consist of ponderable matter? Were it so, 
would it not be attracted about the planets with forces propor- 
tioned to their weight, respectively? and becoming of unequal 
density, would not the diversity in its density, thus arising, 
affect its undulations, as the transmission of sound is influenced 
by any variations in the density of the aériform fluid by which 
it is propagated ? 
With esteem, 
I am yours truly, | 
Rosert Hare. 
Demonstration pe all Matter is Heavy. By the Rev. W1ut1am WHE- 
weELL, B. D., Fellow of Trinity cies and Professor of Moral 
Philosophy. [Read February 22d, 1841.] 
The discussion of the nature of the grounds and proofs of the oat 
general propositions which the physical sciences include, belongs rather 
to metaphysics than to that course of experimental and mathematical 
investigation by which the sciences are formed. But such discussions 
seem by no means unfitted to occupy the attention of the cultivators of 
physical science. The ideal, as well as the experimental side of our 
knowledge, must be carefully studied and scrutinized, in order that its 
true import may be seen; and this province of human speculation has 
been perhaps of late unjustly depreciated and neglected by men of 
science. Yet it can be prosecuted in the most advantageous manner 
by them only : for no one can speculate securely and rightly respecting 
the nature and | Proofs of the truths of science without a steady posses- 
—_ of femme nae >and solid, portions of such truths. A man must be 
c. — a natural historian, in order 
concerning mathematics, and mechanics, 
