14 Canadian Record of Science. 
and comparatively shallow waters in front, some tempera- 
tures were taken, at different periods of the summer, which 
establish the fact that notwithstanding the presence of 
islands in the sound, and of land on all sides, at no place 
more than two to three miles distant, the deep depressions 
or pools in the bottom of the sound, in some places exceed- 
ing sixty fathoms in depth, retain their cold water through- 
out the year. The change observed at the bottom between 
the beginning of May and the end of August did not exceed 
3.5°, whilst in the same period the variation at the surface 
was 25.5°. The observations have sufficient interest to be 
given here :— 
Time. Depth. Air. Surface. Bettom. Sky. 
May 2nd,noon.... 62 fms. 48° 365 22 35.7° Clear 
Aug. 28rd, 5p.m.. 48 “ 64° Glee 39.2° Some clouds 
Oct. 15th, 4.10 p.m. 57 “ 57° SEOs 39° Overcast 
How far the cold waters of these deeper pools in a land- 
locked harbor like Parry Sound, which is largely free from 
the direct influence of outside currents, are subject in sum- 
mer to much change, not merely in temperature but 
through circulation, is worth considering. 
Referring to the Georgian Bay generally, Commander 
Boulton infers from the temperatures which he has taken 
that, in the early spring of the year, the whole column of 
water is at nearly the surface temperature, and that the 
effect of the summer’s heat is to warm up the bottom water 
to about the temperature of water at its greatest density, 
WAZ BO eee 
INFLUENCE OF LAKE SUPERIOR WATERS ON GEORGIAN BAY 
TEMPERATURES. 
In considering why the bottom waters in the Georgian 
Bay retain so low a temperature throughout the summer, 
regard must be had to the direction of the inflow of the 
waters from both Lake Superior and Lake Michigan. A 
reference to a chart of the Great Lakes willhelp to explain 
this, The waters of Lake Superior—always cold—tind 
