BIGELOW: EXPLORATIONS OF THE COAST WATERS. 237 



tare by l°-2°. But this would necessarily raise its salinity as well, 

 Atlantic water being considerably salter even than Labrador water, 

 as demonstrated by the Seneca and Scotia stations off the southeast 

 corner of the Grand Bank. Hence, if any large amount of mixed 

 water of this sort reached No\-a Scotia, its effect would l)e even more 

 unmistakable, in raising the salinity of the coast current, than that 

 of pure Labrador water, even if temperature did not betray it. But 

 we have found nothing of the sort, low salinity prevailing all along 

 the coast from Cabot Strait (Dawson, 1913) to Banquereau (p. 236) 

 and thence to Shelburne (p. 182). Furthermore, the work of the 

 Seneca failed to reveal any dominant flow to the southwest across 

 the Grand Banks, the current there being tidal (Schott, 1897, John- 

 ston, 1913, 1915). In short, hydrography argues against the idea that 

 the Labrador Current exerts any direct influence on the Nova Scotian 

 long-shore current; if it does, it is insufficient to have any appreciable 

 effect on the salinity or temperature of the latter. 



This is an appropriate place to point out, what the hydrography of 

 the outflow from the Gulf of St. Lawrence proves, that the mere exist- 

 ence of a minimum temperature layer even as cold as 0° in summer at 

 100 meters or so, with warmer water above and below, is not a criterion 

 for the presence of polar water. True, such a minimum temperature 

 layer is characteristic of polar waters (Nansen, 1902; Helland-Han- 

 sen, and Nansen, 1909; Knudsen, 1899; Matthews, 1914). But it 

 can be equally produced in partially enclosed coastal waters, where 

 the surface layers are subject to an extremely rigorous winter climate, 

 alternating with considerable solar warming in summer; and where 

 at the same time, the depth of water is great enough to allow a more 

 or less constant inflow of warmer ocean water below the depth to which 

 winter cooling penetrates. Thus, in the Gulf of St. Lawrence, local 

 air temperatures, without any considerable accessions of polar water 

 (Pawson, 1907, Krummel, 1907), produce a vertical range of tem- 

 perature in summer from 15°-18° on the surface to about .56° to 1.1° 

 at 100 meters, warming to about 4.4° at 400 meters (Dawson, 1913); 

 and a similar, though less pronounced minimum layer obtains, in some 

 summers, even in the Gulf of Maine (p. 222), due to the same causes. 

 But wherever such a minimum layer is colder than about —1°, as is 

 the case in the Labrador Current (Matthews, 1914) it is positive evi- 

 dence of Polar water, for nowhere, on either side of the North Atlantic, 

 does winter cooling alone produce such a low temperature. 



In the present connection the important feature of the Cabot 

 Current is its effect on the Gulf of Maine. Although the Current is 



