BIGELOW: EXPLORATIONS IN THE GULF OF MAINE. 61 



revealed no appreciable change in temperature of the bottom water 

 in that region from the middle of July to the 25th of August. But 

 comparison between the serial temperatures in Massachusetts Bay- 

 July 9-13 (Stations 1, 5, 6) and those on August 31 (Stations 44, 45, 46) 

 shows a marked warming of the bottom water down to forty fathoms, 

 though, as pointed out above (p. 44), the surface water had cooled 

 appreciably during the interval between our two visits. Stations 6 

 and 45 are especially instructive because made within a few miles of 

 each other. The surface temperatures (fig. 9) were 61° at both; but 

 whereas on July 14 the temperature was 43° at ten fathoms, and 

 41.3° at twenty-seven fathoms, on August 31 the ten fathom tem- 

 perature had risen about 10°, i. e., to nearly 53°. At thirty fathoms 

 there was also a rise; but of only 3°, i. e., to 44.7° the bottom tempera- 

 ture, in forty fathoms, being 43.1°. And the curves for Station 45, 

 if continued downward, suggest that 40.3° would not have been met 

 until a depth of about sixty-five fathoms was reached instead of at 

 forty to forty-five fathoms as in early July. But as we were unable to 

 make stations in the deep parts of the Bay on our second visit, it is 

 impossible to state how far such a reconstruction would be correct, 

 though we can safely say that the whole water-mass over the shallower 

 parts of the Bay down to at least forty fathoms was several degrees 

 warmer at the end of August, than it had been the beginning of July, 

 except for the surface, which was slightly colder. 



One Station, (43), some twelve miles off Cape Cod, over the inner 

 edge of the deep basin, in ninety-five fathoms, remains to complete 

 our survey of the temperatures. With a surface reading of 60°, the 

 intermediate temperatures at Station 43 below five fathoms were from 

 l°-3° warmer at all depths than they were in ]\Iassachusetts Bay two 

 days later (Stations 45 and 46). The temperature curve (fig. 10) is a 

 regular one, without sudden angles. Comparison with the curve at 

 Station 7 (fig. 10) shows that the bottom water at Station 43 was 1° 

 warmer, 41.3° instead of 40.3°; and that it was not encountered until 

 a depth of eighty fathoms was reached, instead of at fifty fathoms, i. e., 

 it was only fifteen instead of seventy-five fathoms thick. Station 43 

 was colder at all depths above seven fathoms, warmer at all depths 

 below that level. 



In considering the diflferences between Station 43 on the one hand, 

 and Stations 2 and 7 on the other, the advance of the season ami con- 

 sequent cooling of the surface must be borne in mind. And this no 

 doubt accounts for the lower temperature down to seven fathoms at 

 the former. But the fact that Station 43 was warmer at all depths 



