Boston Lightship (Figure 4, Table 4) 
The 1957 surface water temperatures in terms of 10 day means 
were generally higher than the mean for the 1925-19l;1 period and were 
for the most part above the 1956 readings. 1957 was characterized by 
early warming, an early maximum in late July and, except for a brief 
period in the fall, by slower than normal cooling. The thermocline be= 
gan to develop in late March and was destroyed by early November; in 
structure it was very similar to that of the previous year. The annual 
mean surface temperature was 50.0 degrees or 1.) degrees higher than in 
1956. 
Salinitieg held higher and more uniform than in 1956. The 
minimum at the surface was about 31.7 °/oo in May with the maxima in 
January, February, March and December of 32.5 °/oo; this gives a range 
of less than 1.0 °/oo contrasted with a range of 2.0 °/oo the previous 
year. As in 1956 bottom salinities were .50 to .75°/oo higher than the 
surface during the period of the thermocline. 
