18 Canadian Record of Science. 
pavied by a light vapour over the water. In the ascent 
from this stratum of air directly in contact with the water, 
to the top of the bank, there was a constantly varying but 
gradually lower temperature. At one and a-half feet above 
the water the readings fluctuated between .5° and 3° lower 
than at one inch above the water, and on the top of the 
bank these fluctuations ranged from .5° to 4.5° lower than 
at one inch. In only one case was the reading on the top 
of the bank higher in range. Four illustrations are here 
given to show the relative temperatures (1) during a con- 
tinuous dense fog, (2) and (3) at different hours on the 
same cloudy day, and (4) at sunset on a cloudy cool day: 
(1) (2) (3) (4) 
9 a.m. 4 p.m. 7 p.m. 7.15 p.m. 
Aug. 16, Aug. 31, Aug. 31, Aug. 28, 
dense cloudy. cloudy—water cloudy— 
fog. absolutely calm. cool. 
Water at 3 ft...... S500 Neola dar GSS EMER orrctetereys Gieze 
Water abiloimes ssa.) la(oe 68° 68 .25° 66.5° 
Air 1 in. above water.. 68.5° 66° 66 .25° Sidi 
Samui ssttss sf Cae tu OGEH Og 63 .5° Glog 05.0° 
manny tits a Ce oe renee ch Geto ire tal Meise Gta oDOC 
soll Gyatite st Seeuare roi ODN Ome 62° 60. 25° 5Dde 
In the case of the second illustration, when the ther- 
mometer at 8 ft. up the bank was placed upon the moist 
ground there, the mercury rose from 638° to 64.5°. On the 
top of the bank, about 300 ft. inland in the fields away from 
the woods, it remained at 62°, but in the woods 200 ft. 
nearer the bank of the river it fell to 60.5°, the thermometer 
in each case being placed at about 18 in. above the ground. 
CONCLUSIONS. 
The readings are suggestive of the condition of probably 
most of the tributaries, from the south, of the St. Lawrence 
and Great Lakes during the hot months of summer. The 
tests were not sufficiently varied, as to place and time, to 
warrant definite deductions, but it may be said, in general 
terms, that these rivers, which in winter are paved with two 
