BIGELOW: EXPLORATIONS OF THE COAST WATERS. 



225 



across the whole breadth of the shelf in the upper layers, though with 

 decidedly salter water below about SO meters, thus corroborating 

 the corresponding temperature profile (Fig. 73). 



The alteration in salinity in the western side of the Gulf from 

 INIay to June, i. e., a decided freshening at all depths down to about 

 100 meters (p. 207), resulting in the disappearance of 33%o water 

 down to 40 meters (Fig. 70, 72), is just the reverse of what takes place 

 in the eastern side. Below 100 meters, however, there was very 

 little alteration in salinity from May to June (p. 207, Fig. 45) in the 

 Western Basin. 



If our September data for 1915 represent the normal salinity for 



300 



Fig. 70. — Salinity profile across the Gulf of Maine, from off Cape Ann (Station 10266) 

 to German Bank (Station 10271), May 4-7, 1916. 



that season, the summer salting of the upper layers in the eastern part 

 of the Gulf must by then have passed its climax, and the salinity 

 have commenced to diminish once more. On the surface, it is true, 

 very little difference is apparent between the charts for mid-summer, 

 and for September (Fig. 18, 67) in that region. But at 40 meters 

 (Fig. 33, 68), the whole eastern half of the Gulf was fresher in Septem- 

 ber than in August, and there is no sign of the tongue of 33%o water so 

 evident in mid-summer, both in 1914 and in 1912 (1914a, pi. 2). And 

 the same generalization holds equally for the 100 meter-level, where 

 the September salinity of the Eastern Basin was only about 33.2%o, 

 as against 33.6-33.8%o in August, 1912; 33.5-34%o, in August, 1914 



