PHYSICAL OCEANOGRAPHY OF THE GULF OF MAINE 
607 
TEMPERATURE AT 40 METERS 
The regional differences that developed in the vertical distribution of tempera- 
ture between various parts of the Gulf of Maine, as the summer advances, tend to 
make the temperature (as plotted in the horizontal projection) more nearly uniform 
in the mid depths than it is at the surface. Thus, all the 40-meter readings for the 
month of August of the years 1912 to 1915 (figs. 52 to 54), and 1922 (omitting for 
the moment the cold summers of 1916 and 1923), have fallen within a range of 6°, 
from a maximum of 11.5° off Lurcher Shoal (station 10031, 1912) to a minimum of 
5.5° off Cape Sable (station 10243, 1914). Only 6 August readings at 40 meters, 
out of a total of 64, have been as warm as 10° to 11°; only 3 cooler than 6°, and 
the great majority have fallen between 7° and 9.5°, irrespective of precise geo- 
graphic location. Consequently, this may be taken as the normal temperature to 
which the 40-meter stratum of the gulf as a whole warms by the end of the summer. 
With so narrow a range, and with the water continuing to warm until well into 
the autumn, a difference in date of a few days one way or the other will be accom- 
panied by a greater difference in temperature, at this level, than any regional differ- 
ence that might be disclosed by a simultaneous survey of the whole western and 
northern part of the gulf. 
Differences between cold and warm years, illustrated by a temperature of about 
8° on August 9, 1913 (station 10088), but only 5.75° at the same locality in 1914 on 
the 22d of that month (station 10254), likewise outweigh the regional differences for 
