586 



BULLETIN OF THE BUEEAU OF FISHERIES 



last half of the month. On the whole, the surface temperature of the gulf may be 

 described as more nearly stationary from July 25 to the end of August than over 

 any equal interval during the spring, on the one hand, or during the autumn, on the 

 other. 



The surface chart for late summer (fig. 46) represents the average state during 

 the last week of August. Deviations in one direction or the other from the precise 

 values there given are to be expected, however, according as the year is warm or 

 cold, the season forward or tardy (p. 626). 



The surface temperature within the gulf rises highest over the western and 

 southwestern parts of the deep basin, at the mouth of Massachusetts Bay, and in 



Fig. 4.5.— Extent of bottom water warmer than C°, last half of June, 1915 



Cape Cod Bay, as outlined by the isotherm for 18°. Within this area readings of 

 20° have been reported on three occasions, namely, twice by Doctor Kendall in the 

 last week of August, 1897, and more recently on August 22, 1914 (station 10254). 

 On the other hand, the lowest surface reading so far recorded for the last week of 

 August in this warm subdivision, more than a few miles out from land, was 17.6° 

 in the western basin on August 31, 1915 (station 10307) . The data from the cruises 

 of 1912, 1913, and 1914, compared with readings taken in August, 1922, and by 

 Doctor Kendall in 1897, show that the temperature first reaches 18° at the mouth 

 of Massachusetts Bay and out over the neighboring^ part of the basin in its ofEng, 



