330 Proceedings of the Royal Physical Society. 
fitted together as to prevent the passage of the water between them. To meet 
this difficulty, he plasters the side of the wall exposed to the current with 
a coating of clay some 2 or 3 inches in thickness; and this clay, as he has 
to travel through the water with it, he carries not in his arms, as in the 
construction of the house, but on his head, supported by his arms. There 
is no doubt that the side of the wall exposed to the current is thus clayed, 
although I cannot well understand how it could withstand the action of 
the water for any length of time. If he bridged the stream in this way 
and clayed his bridge, it is clear that he would have always a large quan- 
tity of water flowing over the top, which would impede his operations ; 
and, to obviate this difficulty, he leaves an opening at either end for the 
passage of the water, to be shut up afterwards. Having finished the wall, 
the next thing to be done is to collect his winter's supply of food. This 
consists of the bark of the ash, the bark and leaves of a certain kind of 
poplar, the bark and leaves of some kind of willows, and the fruit of the 
alder. A large poplar tree of about a foot in diameter, two beavers can 
cut down in half an hour's time. It is afterwards cut into lengths of 
about 5 feet ; and when he has got enough, he makes a road to the stream 
from 3 to 6 feet wide, by cutting down trees or shrubs which may be in 
his way. If the road be inclined towards the stream, he rolls the wood 
down before him; but if it be level, or nearly so, he takes hold of the 
wood by his teeth, and carries it forward. In the water he always trans- 
ports wood or branches from one spot to another in a similar manner. 
His wood will, of course, float in the water, and, if left to float, would 
soon become embedded in the ice, which in ordinary winters, in this cli- 
mate, is about 5 feet in thickness ; he therefore takes it to the bottom of 
the dam, which has a depth of water of from 10 to 12 feet, and either 
fastens it on end in the mud, or covers it with stones, to prevent its rising, 
and it will thus at all times be available for his purpose. He is now 
nearly ready for the long winter. There is, however, something more to 
be done. I have mentioned that he digs a subterranean passage from his 
house to his dam ; on each side of this, and in some instances widely 
apart, he makes holes about 5 or 6 feet in the bank, generally communi- 
cating in the interior with one another, and with the main entrance to 
the lodge. In one of these he takes his food, for he seldom or never eats 
where he sleeps. 
The female has generally from three to six young at one time ; the 
period of gestation is four months ; and the young are produced, or first 
see the light, about the middle of May, and in the following August 
assist in building the lodge. The young and old work together. When 
about a year old, they start in pairs to form new settlements, provided, 
like the best of colonists for a new country, with nothing else but good 
strong limbs and a fine set of teeth. If there be an odd-fellow, he goes on 
his travels alone, and forms a small bachelor establishment for himself for 
the winter, unless, indeed, he meets a friend with kindred sentiments by 
the way. Sometimes two of the year-olds remain in the old house for 
another year, in which case the family in the following May is a large 
one, never, however, numbering more than twelve individuals. The 
usual number found in a lodge is from four to eight. They never build 
their lodges close together — they are generally from a quarter to half a 
mile apart. This no doubt arises from the circumstances that they cannot 
well dam the rivers or streams, and find a sufficiency of food, at shorter 
distances. The beaver remains shut up for the whole winter; during the 
day always asleep, and during the night taking his bath and his meals. In 
spring, however, he sometimes makes a hole in the ice to have a look at 
ttie country around him. I do not know how he manages to do without 
air; so far as I could discover, there are no air-holes about his premises. 
