156 ON THE FBONTIEE. 



and plastering the prepared mud just as a mason would 

 apply his mortar with his trowel. Authority, worthy of high 

 respect, says this is not so, is physically impossible ; but 

 many times I have seen the unmistakable print of the 

 beaver's tail on his mud -mortar. 



Probably the beaver commences the construction of his 

 dam by loading branches with mud until they sink, conveying 

 them in his mouth to their assigned place, and there plaster- 

 ing them down with his tail. But however he may proceed, 

 the building of a beaver-dam is an undertaking necessitating 

 great forethought, patience, and labour, and must require 

 the combined industry of many animals all the summer to 

 complete it. 



Dam-building is not the result of an irresistible impulse or 

 instinct in the beaver, for in waters frequented by that 

 animal, which are naturally both sufficiently extensive and 

 unfluctuating in level to serve their purposes, they do not 

 make any dams ; and there is also a great range of ability 

 shown in their construction, as it is quite common to find on 

 the same stream dams of first-class workmanship, and some 

 that are far otherwise. 



The trap used for catching the beaver is made on the 

 same principle as the ordinary gin, but has two springs. 

 These springs have to be of the best steel, and very well 

 tempered, as they cannot be too quick, and are, besides, 

 required to be so strong that great knack and power is 

 necessary to set the trap. Their jaws are about six inches 

 across and three high, forming, when open that is to say 

 when the trap is set a six-inch square. To the trap is 

 attached about twelve feet of chain (trace chain is what we 



