i6 THE POPULAR SCIENCE MONTHLY, 



ground, a distance easily reached while sitting upon the tail and 

 haunches, the tree is gouged around in a complete circle, equally on 

 all sides, but gradually growing deeper and deeper with each circuit, 

 forming, as it were, two cones whose points meet at a common center. 

 When the space chipped out proves too narrow to admit the head, the 

 teeth are applied above and below, as the woodman plies his axe, 

 until the desired result is obtained. Steadily and faithfully he labors, 

 rarely resting, and then but to take a refreshing bath in the nearest 

 pool. At the last he frequently pauses, and, erecting himself upon his 

 hind-legs, feels the trunk with his paws, as if to determine which way 

 it shall fall, or whether it shows any signs of yielding ; finally, when 

 perhaps but an inch or two of the heart remain uncut, he gnaws vigor- 

 ously upon the side toward which he desires it to fall, and, as the warn- 

 ing crack is heard, whips himself with great celerity and adroitness to 

 the opposite side to avoid being crushed in its descent. Next the 

 trunk is divided into lengths, and dragged by aid of teeth, paws, and 

 chin to the water, where it is floated to the dam or storehouse. When 

 large trees are chosen, they almost invariably stand upon the margin 

 of the water, into which they are made to fall ; but small growths are 

 frequently sought at considerable distances, and regular paths or "run- 

 ways " are beaten in the tall grass and ferns where such have been 

 transported. The number of trees felled by one small colony is sur- 

 prising, and the regularity of the stumps left might lead one unac- 

 quainted with the cause to believe them the result of human industry. 



When the beaver selects a home on the bank of lake, pond, or 

 stream whose waters are both deep and abundant, dams are rendered 

 unnecessary, and even houses are not always constructed, but instead 

 dwellings are hollowed out from the banks. But on shallow, narrow 

 waters, dams are indispensable in order to secure sufficient depth to 

 allow of concealment and free movement beneath the surface, as well 

 as to prevent obstruction by ice : the entrance to the dwelling or store- 

 house is always beneath the water, which acts not only as a doorway, 

 but as a safeguard from predatory enemies. 



In the building of a dam considerable engineering qualities are de- 

 veloped. It is seldom seen as a mere straight embankment, but goes 

 winding across the stream in graceful curves, bending hither and 

 thither to present its convexity toward the swifter flowing current or 

 deeper waters, taking advantage at the same time of all natural in- 

 equalities, now a rock, here an islet, and there a hillock. Trunks of 

 trees are carefully intermingled with clods of earth, stones, and twigs, 

 and every crevice is carefully stopped with mud or clay for greater se- 

 curity ; and, when all is finished, the whole presents a structure of al- 

 most incredible solidity and compactness, frequently increased by the 

 roots of willow and larch which spring up with all the regularity of 

 a hedge. In the neighborhood of Washington Mine, Lake Superior, 

 may be seen a dam with a total length of fifteen hundred and thirty 



