223 
weight as any criterion, that cold neither gives nor takes any material par- 
ticles from bodies, and therefore cannot in any sense be regarded as essential 
matter.” 
I think the fact ought to be put on record, as is done here, that water is the 
almost solitary exception among material bodies which exhibits contraction 
by heat and expansion by cold. It is well known that the densest water is 
to be found at a temperature of 4° centigrade, or 39|° Fahrenheit, and that 
from the point of its greatest density down to freezing-point the water 
expands. Now that is a wonderful provision of nature, because the water is 
the habitat of a very large number of created beings, and if it were not for 
this provision life would be destroyed in the colder regions. Suppose water 
contracted continuously instead of expanding with cold : as fast as it froze 
on the surface, the particles of ice would fall to the bottom, and we should 
have the ocean frozen into one solid lump. This is a most important fact, 
which I think Mr. Reddie might have referred to with considerable force. 
(Hear, hear.) At the bottom of the same paragraph Mr. Reddie says, — 
“ While if we say that matter must be colourless, what is that but to say 
that it is invisible ? ” 
Now that I really cannot admit. If in summer time we take a glass of 
water from a cool limpid stream, neither the limpid water itself nor the glass 
which holds it contains any colour, and yet neither of them is invisible. 
The presence of colour is not necessary to visibility. In the 10th paragraph 
Mr. Reddie objects to some terms commonly used in physical science ; but 
his objection, so far as I can see, is made without good reason. He says : — 
“ Glass, when formed and joined in a certain way by means of fire and 
then allowed to cool — for the cold is as necessary as the heat, you know, to 
produce the solidity— has certain qualities of hardness, solidity, and elas- 
ticity ; but these qualities it has as a whole only from some law which regu- 
lates the cohesion of its particles—' 4 the attraction of cohesion ’ it is scientifi- 
cally, or rather technically called ; but if by attraction we mean 4 drawing 
together,’ and by cohesion ‘ sticking together,’ and translate the phrase, it will 
stand 4 the drawing together of that which is sticking together,’ and, you will 
agree with me, this technical phrase adds little to our ideas on the subject.” 
I do not agree and I cannot agree with Mr. Reddie in this passage. The 
term 44 cohesion ” is a qualitative addition to the term 44 attraction,” and we 
say 44 the attraction of cohesion ” just as we say 44 the attraction of gravita- 
tion,’ the term 44 gravitation ” being also a qualitative addition to the term 
4> attraction.” If you were to Germanize it, the attraction of gravitation 
would be the 44 weight attraction,” and the attraction of cohesion would be 
the 44 stick-together attraction,” and I should have no objection to that at all. 
Suppose these particles of powdered glass which Mr. Reddie speaks of were 
scattered through a portion of infinite space at such a distance from all other 
bodies as that their weight attraction to each other would exceed the weight 
attraction of the stars. They would come together by their weight attrac- 
tion, but they would then be a mere aggregation of particles — they would 
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