94 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
we got a bottom reading of 39.2°. In the deep basin off Cape Ann, 
Verrill’s readings, in ninety, one hundred and eighteen and one hun- 
dred and fourteen fathoms, are 40°, 43°, 39° and 39°, at three stations 
near together. But the fact that we found a thick layer of bottom 
water very uniform in temperature in this region, suggests that the 
discrepancy in his readings was due to the faulty instruments. And 
it is at least suggestive that the average of his four readings in the 
basin is 40.2°, 7. e., within .1° of our observations. Off Cape Cod, 
too, in 142 fathoms, close to Station 43, the bottom temperature in 
1874 was 39° or 42°, agreeing fairly well with our record of 41.3° at 
Station 43. And the difference in depth is not significant in this 
case, because we encountered the uniform bottom water at 50 
fathoms. On the other hand Verrill records a bottom temperature 
of 52° in 100 fathoms southwest of Jeffrey’s Bank, where in 1912 the 
bottom reading, to judge from neighboring stations, must have been 
little, if any above 40.3°. And our entire experience makes it so 
improbable that the 100 fathom temperature is as high as 50° anywhere 
in the Gulf, that such a reading is best credited to the unreliability 
of the instrument with which it was taken. On the whole the bottom 
temperatures in Massachusetts Bay, in the western basin, and in 
the trough west of Jeffrey’s Ledge were practically the same in 1873 
as they were in 1912. But Verrill’s readings for the northeast corner 
of the Gulf are so consistently lower than ours, that it is probable that 
the bottom water in that region actually was from 1° to 3° colder in 
1873 and 1874 than it was in 1912. His records for 1874, (1875, 
p. 413) agree in a general way with our work in 1912, but as the 
same unreliable thermometers were used, and only one reading taken 
at each station, it is unwise to lay stress on them. 
Dickson’s, (1901) charts show the salinity of the eastern half of the 
Gulf as below 32%po the Bay of Fundy 31% or lower, and Massachu- 
setts Bay as below 32 for August, 1897 (no salinities are given for the - 
remainder of the Gulf for these months). But on examining his 
tables, which give the tests of the water samples on which the charts 
are based, I did not find a single record from within the Gulf for either 
month, which suggests that the salinity credited in his charts to the 
eastern half of the Gulf was deduced from the low salinities revealed 
by several water samples taken in that month off the Nova Scotian 
Coast. But our own records show that his reconstruction of this 
region was probably incorrect, because it is certain that in August, 
1912, there was an indraught of Atlantic water with salinities of 32.8 
or more into the eastern part of the Gulf, and we have no actual data 
