OF WATER; AS EVIDENCE OF DESIGN IN NATURE. 247 
of a few hundred fathoms of water added to the degree of 
condensation reached at a rather low temperature, the water 
would become solid; that is to say, a mass of ice throughout 
a depth of several thousand feet from the floor. Throughout 
this zoue life would be absent ; the currents of the ocean would 
be restricted to the surface, and the whole physical arrange- 
ments now working harmoniously, would be impossible. All 
this has been rendered impossible owing to the incompressibility 
of water, in which it differs from all other bodies, and is there- 
fore abnormal. 
As a digression for a moment, I may observe that it is owing 
to this condition or attribute of incompressibility that the 
flanges of a propeller are so effective in forcing a ship of the 
largest size at a high speed through the water. When we 
examine one of the beautiful models of our ocean liners, we are 
struck by the diminutive size of the propeller at the stern with 
the huge mass which by its rotation and the slight angle at 
which the flanges ure set to the axis, it is capable of forcing 
the ship through the ocean at a high speed. We have to recoliect, 
however, that the water when thus acted upon is practically 
a solid. There is not time for it to give way, and being invom- 
pressible it cannot yield to the lateral pressure exercised 
by the flange, any more than if the waters were solid or 
nearly so. We shall now return to our subject. 
It is to be observed, moreover, that these two attributes of 
the maximum density and incompressibility work harmoniously 
together in the physical system of the globe. It is owing to 
this that the ocean at its profoundest depths is never frozen, 
though it approaches within a few degrees of the freezing point. 
The currents of warm water, such as that of the Gulf Stream, 
which is constantly pouring water at a high temperature into 
hizh latitudes, are necessarily replaced by cold polar waters 
moving slowly in both directions over the bottom of the ocean 
towards the equatorial regions. If the waters were compressible, 
or if the conditions regarding density were otherwise from 
those above described, this circulation of the warm and cold 
waters would be rendered difficult, if not impeded because the 
fruzen polar waters would not be able to rise to the surface. 
As regards lakes ; for similar reasons the waters even in deep 
lakes are never frozen at the bottom; the ice as it forms at the 
surface owing to the cold of the air, constantly ascends; thus 
tending to keep the underlying waters in a state of fluidity. 
The soundings over the Lake of Geneva show that the lowest 
waters are at a temperature above freezing point. From a 
R 
