16 Canadian Record of Science. 
Bruce Peninsula, and constitute a barrier to the extension 
easterly of these warmer Michigan waters. The few sur- 
face and bottom readings obtained by the United States 
Lake Survey would appear to justify the suggestion, as the 
waters in the broad line of flow from the Straits of Mackinac 
to Sarnia indicated 10° warmer at the bottom and 6° to 7° 
at the surface than those in the Central Basin to the east of 
this general line. 
YAMASKA RIVER. 
Two or three weeks holiday, spent last August at 
Yamaska Mountain, on the banks of the Yamaska River, 
gave me the opportunity of making numerous thermome- 
trical tests of the relations between the water and the over- 
lying air, and, inferentially, of the influence which water in 
larger bodies must have on the temperature and agricul- 
tural capabilities of the neighboring land. 
The river here is from 300 to 400 feet wide and from 10 
to 15 feet in depth. and flows in a very serpentine course 
through a broad stretch of level country, the only con- 
spicuous break immediately near being the _ isolated 
Yamaska Mountain, which, about halfa mile back from the 
river, rises precipitously to a height of about 900 feet, and 
is, from summit to base, clothed with pines, spruces, maples 
and other trees. On the Abbotsford side, the incline is 
gradual, and affords both room and protection for the ex- 
tensive orchards which there are laid out with a semblance 
of mathematical exactitude on the mountain side. Viewed 
from the mountain, the great plain here has been almost 
denuded of its woods, and, with the tracery of unsightly 
fences, is at every point subdivided into cultivated farms. 
The wind has, therefore, but little to break its force as it 
sweeps over the great plain and past the mountain sides. 
Where our headquarters were on the banks of the river, in 
full view of the sombre mountain which lay about half a 
mile away, the gales were frequent, sometimes violent. 
The river, however, flowed in its tortuous course between 
precipitous banks of from 15 to 20 feet high, and generally 
