OF WATER; AS EVIDENCE OF DESIGN IN NATURE. 249 
the severe frost of a January night. The importance of this in the 
economy of nature is pointed out by Professor Hull; but I wonder 
that, as a geologist, he did not lay some stress upon the important 
work which it does in the degradation of mountains and of sea- 
cliffs as well as in pulverising the soil during frost, with beneficial 
results known to every agriculturist. 
(2) But another deduction follows from this law, and from the 
converse fact, that pressure acting hydrostatically upon ice causes 
it to melt or liquefy. This was splendidly demonstrated years ago 
by Helmholtz and others.* Now, as pressure upon ice tends to its 
liquefaction, so pressure upon water at 0° C. prevents its congelation. 
This is the true explanation of the fact that water can exist in the 
liquid state at ocean-depths at very low temperature ; and we cannot 
therefore follow Professor Hull, when (in the second part of bis 
paper) he attributes this fact to the incompressibility of water. 
Pure water is compressible to only about one twenty-thousandth of 
its bulk ; but most water, as it occurs in nature, holds atmospheric 
or other gases in solution (a fact which is easily demonstrated), and 
is rather more compressible accordingly. Still, for practical purposes 
water may be said to be incompressible, and the important results 
of this have been dealt with by Professor Hull. 
(3) In connection with this subject there is however one point 
which has not been touched upon in the paper, although it must be 
of philosophical interest to many members of the Victoria Institute. 
We can follow Professor Hull in pointing to the abnormal behaviour 
of water in expanding from 4° C. to 0° C., with all its important 
consequences, as one of the strongest evidences of Creative Design 
which Physical Science discloses to us, because it is wnque among 
liquids. But we must not confound this fact with the other fact, 
that in the act of congelation it undergoes further expansion, since 
in this matter it is not unique. Bismuth and cast-iron undergo 
similar expansion ; and in the case of the former, the fact is turned 
to account in using an alloy of bismuth and lead for casting type- 
metal, the expansion of one metal compensating for the contraction 
* Liquefaction under pressure and regulation is a most important 
factor in the flow-movement of glaciers. See my paper on “The 
Mechanics of Glaciers,” in the Quarterly Journal of the Geological Society 
(February, 1883). 
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