MAY. 103 



the water, on which it swims with about half its body sub- 

 merged. Now it has need to guard against enemies from 

 above and below : eyes which would see well in the air, 

 would not see well in the water, on account of the difference 

 in the density of these media, and besides, one pair of eyes 

 could not be in both the air and water at once. To obviate 

 this inconvenience, the Gyrinus has one pair just above the 

 surface, and another pair just below, very close together, yet 

 sufficiently separate to be in different elements. Insect 

 anatomists find that the two eyes, that is, the upper and 

 lower eye on each side, are joined internally, and connected 

 with one optic nerve, — an example of economy of materials 

 by no means uncommon. 



C. — Going down to Spafford's bridge yesterday, I ob- 

 served that the river had overflowed its banks, and inun- 

 dated the extensive meadows and low lands on each side, 

 so that it looked like a large lake : the road was impassable 

 for foot passengers. 



F. — These freshets, as they are termed, occur every spring, 

 and are caused by the melting of the accumulated snows of 

 the past' winter. It is true our snow has disappeared some 

 time, and the roads are comparatively dry, but it is in the 

 mountains that these freshets originate. The snow there 

 does not melt so soon as in less elevated regions ; and as all 

 the springs and rivers have their sources among the hills, 

 they are comparatively little affected, until the melting of 

 the mountain snows. — On such of our rivers as have steep 

 banks, as the St. Maurice and the Magog, I am informed it 

 is not uncommon for slides to occur at this season. Heavy 

 spring rains undermine the earth, while yet frozen, and loosen 

 it from the subsoil, when large portions of the surface, with 

 all their trees and bushes, slide off the rock beneath, and 



