BIGELOW: EXPLORATIONS IN THE GULF OF MAINE. 43 



southeast of Nova Scotia (Dickson, 1901) besides a series of surface 

 and bottom temperatures by the Albatross (Townsend, 1901). 



Surface temperature, July-August, 1912. — The surface temperature 

 was taken hourly, day and night, throughout the cruise; and the read- 

 ings are plotted on the chart (Plate 1). When I came to check up 

 the results, one interesting anomaly became apparent, namely, that 

 the surface temperature at each station is from .5° to 1° lower than the 

 next reading on either side of it. This discrepancy is probably due to 

 the method of observation, the readings at the stations being taken 

 with the thermometer hanging a foot or so below the surface, whereas 

 the instrument dragged on the actual surface when the vessel was 

 under way. 



The chart shows that so far as surface temperature is concerned the 

 Gulf of Maine can be divided into two general regions, one with tem- 

 peratures of 60° F or over, both day and night, in July and August, 

 the other with temperatures below 60°. In a general way the first 

 includes the whole of the southern and central parts of the Gulf, 

 i. e., Massachusetts Bay, and the off-shore waters south of 43° 21' N. 

 Lat., as far east as 66° 45' W. Long., but it does not reach the Nova 

 Scotia coast. Over all this area the daily average of the surface water 

 was about 61° and the diurnal warming, touched on below, consider- 

 able. But though Massachusetts Bay as a whole belongs to the warm 

 division, lower temperatures were observed along the northeast coast of 

 the Bay, near Eastern Point, off Race Point (Station 44, 58°); off 

 Baker's Island, and notably near Boston Light-ship (July 15, 58°) 

 where two days before a temperature of 63° was observed. And on 

 July 23 a band of water of only 56° was found extending from 

 Gloucester around Cape Ann for some ten miles northeasterly, i. e., 

 covering a region where a few days before temperatures above 60° were 

 found. 



The temperature was above 60° in Ipswich Bay, north ofCap e 

 Ann. But when we entered the passage between the Isles of Shoals 

 and the mainland, the surface temperature dropped several degrees, 

 the readings here being 55°-57°, and working northeastward, a con- 

 tinuous belt of this cold water was found lying next the coast. 

 From the Isles of Shoals nearly to Cape Elizabeth this cold band 

 was about 15 miles broad; south of the Isles of Shoals it narrowed 

 suddenly, the 60° curve touching the coast somewhere between Station 

 10 and the mouth of the Piscataqua River. The cold water does not 

 reach Cape Ann except sporadically, an instance, as noted above, 

 being July 24th, when, strong northerly gales for the three preceding 



