ta 
392 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
face 26.18, at 45 fathoms, disregarding pressure, 26.30); and its , 
stability might be expected to increase as warming of the surface 
progresses. Thus the process of winter cooling on the surface, with 
its consequent inversion of density, had come to an end by the begin- — 
ning of March at the mouth of Massachusetts Bay. 
It was a month before the BLuE WrinG resumed work; but in the 
meantime Mr. Welsh had commenced his haddock investigation at 
Gloucester, and on March 19, he occupied two hydrographic stations 
at very nearly the same locality as our last station, nine miles south- 
east from Cape Ann, in 45 and 65 fathoms of water. Mr. Welsh’s 
temperature records show a decided rise on the surface, which had 
warmed to 39°, with the same temperature at 48 fathoms, the latter 
being unchanged from the last BLuE Wine station. At 65 fathoms 
the temperature was 38.8°, 1.5° colder than I found it at that depth, 
and, indeed, generally over the bottom of the western half of the deep 
basin, in summer. The salinity proved to be 33.17%, at the bottom, 
at both stations, a decided rise from two weeks previous; and inter- 
esting further because the deeper sample (65 fathoms) came from a 
circumscribed basin, the shallower one from its rim, thus repeating 
our experience in this same basin in July (Bull. M. C. Z., 1912, 58, 
p- 65), when the bottom salinity was found to be the same as the 
salinity on the bottom over the enclosing shoal. At the surface, over 
the deep basin, the salinity was 32.84% , precisely the same as it was 
when the BLuE Wing last visited this region: but over the rim it 
was decidedly salter (33.01% c): probably an evidence of vertical stir- 
ring by tidal currents. 
On April 3, the Bur Wine occupied a station some five mils 
southeast of Gloucester. By this time the surface temperature had 
risen to 39.3°, being practically uniform down to 30 fathoms, and 
slightly colder, 39.1° at the bottom, in 42 fathoms, the latter reading 
showing a rise of only .1° from Mr. Welsh’s records two weeks before. 
And the fact that the temperature of the entire column of water had 
risen slightly is good proof that tidal currents still caused active 
vertical circulation, in spite of the increasing vertical stability of the 
water, the conductivity of sea water being too slight for us to suppose 
that the warmth of the surface had thus been propagated downward. 
But though the temperature had followed the expected course, the / 
salinity had undergone a very striking change, for while the bottom 
and intermediate waters continued to show the progressive increase In 
saltness which had been taking place during the winter, with the very 
high readings of 33.12%, on the bottom and 33.03%p> at 25 fathoms, 
