482 
CURRENTS AND WHALING. 
to the anomalous periodic changes that are known to occur, placing 
all calculations at nought. 
The trades, the monsoons, and other steady or periodic winds, as 
well as the variable winds of the temperate zones, are either caused 
or much influenced by the manner in which temperature is distributed 
over the surface of the ocean, by the polar and equatorial streams. It 
is therefore proper that, as immediately connected with this subject, 
we should mention the spaces which lie between the zones of the trade 
and westerly winds, and which are usually the seat of light variable 
winds and calms. The existence of such a zone in the North Atlantic 
has long been known, and we have assured ourselves of the existence 
of similar zones in the other oceans, though not to so great an extent. 
They lie on each side of the parallels of 30° in both hemispheres, and 
are about three hundred miles in breadth. Leaving out of account the 
effect of the great currents of the atmosphere, we find this space to 
be a sort of eddy, in which the polar and equatorial flow of waters 
neutralize each other, and where therefore, all the floating matter that 
is brought by both must accumulate. I shall have occasion to refer to 
this view of these zones hereafter, as connected with the subject of 
whaling. 
If, however, the view I have taken of the flow of the waters of the 
ocean and their results be correct, which the facts we observed and 
those I have quoted from the authority of others, scarcely leave a 
doubt of, we may see the admirable provisions of nature by which 
the Creator has regulated the fluid mass of the ocean, in its endless 
gyrations seeking to attain a state of equilibrium which it never 
reaches, at the same time and by the same course distributing the 
excess of the tropical heats throughout the whole surface of the globe, 
and bringing towards the equator the icy masses which would other¬ 
wise accumulate in the frozen zones. 
But, putting aside the partial observations that have been detailed in 
the preceding pages, relative to the direction and extent of the great 
streams and currents of the ocean, whether surface or submarine, the 
habits of the spermaceti whale alone would furnish strong circum¬ 
stantial evidence that such currents do exist, and that they are variable 
in their strength, and even in direction, according to the season. 
It is well known to whalers that the favourite and appropriate food 
of the sperm whale is a gelatinous medusa ; which, however, has not 
as yet received from naturalists much attention. It may, however, be 
advanced as certain that this molluscous animal most abounds in the 
higher latitudes of both hemispheres, which would therefore seem to 
be the places in which it is produced, and to which its habits are best 
