970 
BULLETIN OF THE BUREAU OF FISHERIES 
to the right of the surface current, the water at 20 to 30 meters 72° and 108° to 
the right of it, respectively. 
This calculation shows that even in winter wind currents are virtually negligible 
in the Gulf of Maine at depths greater than, say, 20 meters, and so weak at 10 to 
15 meters that they can oppose but little resistance to hydrostatic forces or to tidal 
oscillations (as deflected by the earth’s rotation), which may tend to drive the water 
in the opposite direction. 
The general effect of the wind on the circulation of the gulf may be summarized 
as follows: In summer the prevailing southerly-southwesterly winds tend to main- 
tain the anticlockwise circulation of the surface water, so far as they are effective at 
all in producing a constant circulation. It is probable, also, that the easterly set 
caused by the wind is chiefly responsible for the accumulation of the surface pool of 
high temperature, though low salinity, in the offing of Massachusetts Bay, which is 
characteristic of July and August. The outflow that takes place southward past 
Cape Cod and over the eastern end of Georges Bank, however, is against the prevail- 
ing wind. In winter the prevalent northwesterly winds assist the southerly drift in 
the western side of the gulf and are the chief cause for the wider dispersal of water 
of low salinity off its northern shore than off the western, but the general movement 
of water inward (northward) along the eastern branch of the basin is contrary to 
the wind. 
Winter as well as summer wind currents are confined to the upper 10 to 20 
meters. Consequently the dominant circulation of the deeper strata does not receive 
its motive power from this source. 
HORIZONTAL TIDAL OSCILLATIONS AS DEFLECTED BY THE EARTH’S 
ROTATION 
Huntsman (1923, 1923a, and 1924) recently has suggested that the tidal oscilla- 
tions deflected by the effect of the earth’s rotation are the chief motive force for the 
great eddies, anticlockwise and clockwise, that occupy the basins and circle about 
the islands and submarine banks in high latitudes. In his own words (Huntsman, 
1924, p. 278), “the rotation of the earth” acts “as an imperfect valve in diverting the 
ebb and flood toward opposite sides of the channels and basins,” thus causing a bal- 
ance of inflow on the one side, of outflow on the other. 
That the earth’s rotation must exert a deflective effect on the tidal currents is 
beyond dispute. It is equally clear that if the oscillatory (back and forth) move- 
ment of the tides of any partially inclosed basin be altered by any agency into a 
progressive forward movement, the current, like any other, will be held against the 
right-hand bank in the northern hemisphere by the deflective force of the earth’s 
rotation, and thus circulate anticlockwise, as Huntsman states. Furthermore, the 
deflective effect of the earth’s rotation as it affects the tidal oscillation, if effective 
at all in this respect, must be most definitely so in regions where tidal currents attain 
considerable velocities at the strength of flood and ebb, as they do in the Gulf of 
Maine. 
Beyond stating this proposition and certain applications of it to definite regions, 
Huntsman has not yet published any discussion of the dynamic principles involved, 
nor am I able to give it the physical analysis necessary for its proof or disproof. 
