THE BEAVER. 435 



its chisel-like teeth cutting a bold groove completely round the 

 trunk. It then widens the groove, and always makes it wide in 

 exact proportion to its depth, so that when the tree is nearly cut 

 through, it looks something like the contracted portion of an 

 hour-glass. When this stage has been reached, the Beaver looks 

 anxiously at the tree, and views it on every side, as if desirous of 

 measuring the direction in which it is to fall. Having settled this 

 question, it goes to the opposite side of the tree, and with two or 

 three powerful bites cuts away the wood, so that the tree becomes 

 overbalanced and falls to the ground. 



This point having been reached, the animal proceeds to cut up 

 the fallen trunk into lengths, usually a yard or so in length, em- 

 ploying a similar method of severing the wood. In consequence 

 of this mode of gnawing the timber, both ends of the logs are 

 rounded and rather pointed, as may be seen by reference to the 

 illustration. In the Zoological Gardens may be seen many ex- 

 cellent examples of timber which has been cut by the Beaver : 

 the logs and cut stumps which are given in the illustration were 

 sketched from those objects. 



The next part of the task is to make these logs into a dam. 

 ]STow, whereas some persons have endeavored to make the Beaver 

 a more ingenious animal than it really is, and have accredited it 

 with powers which only belong to mankind, others have gone to 

 the other extreme, and have denied the existence of a regularly 

 built dam, saying that it is entirely accidental, and caused by the 

 logs that are washed down by the stream, after the Beavers have 

 nibbled off all the bark. 



That this position is untenable is evident from the acknowl- 

 edged fact that the dam is by no means placed at random in the 

 stream, just where a few logs may have happened to lodge, but is 

 set exactly where it is wanted, and is made so as to suit the force 

 of the current. In those places where the stream runs slowly, 

 the clam is carried straight across the river, but in those where 

 the water has much power, the barrier is made in a convex shape, 

 so as to resist the force of the rushing water. The power of the 

 stream can therefore always be inferred from the shape of the dam 

 which the Beavers have built across it. 



Some of these dams are of very great size, measuring two or 

 three hundred yards in length, and ten or twelve feet in thickness, 

 and their form exactly corresponds with the force of the stream, 

 being straight in some parts, and more or less convex in others. 



