222 APPENDIX. 



real service ; and at the same time it discovers such a degree of 

 sagacity and foresight in the animal, of approaching evils, as is 

 little inferior to that of the human species, and is certainly peculiar 

 to those animals. 



The beaver-dams differ in shape according to the nature of the 

 place in which they are built. If the water in the river or creek 

 have but little motion, the dam is almost straight ; but when the 

 current is more rapid, it is always made with a considerable curve, 

 convex towards the stream. The materials made use of in those 

 dams are drift-wood, green willows, birch and poplars, if they can 

 be got ; also mud and stones, intermixed in such a manner as must 

 evidently contribute to the strength of the dam ; but in these dams 

 there is no other order or method observed, except that of the work 

 being carried on with a regular sweep, and all the parts being made 

 of equal strength. 



In places which have been long frequented by beaver undis- 

 turbed, their dams, by frequent repairing, become a solid bank, cap- 

 able of resisting a great force both of water and ice ; and as the wil- 

 low, poplar, and birch generally take root and shoot up, they by 

 degrees form a kind of regular- planted hedge, which I have seen in 

 some places so tall, that birds have built their nests among the 

 branches. 



Though the beaver which build their houses in lakes and other 

 standing waters, may enjoy a suflScient quantity of their favourite 

 element without the assistance of a dam, the trouble of getting wood 

 and other necessaries to their habitations without the help of a cur- 

 rent, must in some measure counterbalance the other advantages 

 which are reaped from such a situation ; for it must be observed, 

 that the beaver which build in rivers and creeks, always cut their 

 wood above their houses, so that the current, with little trouble, 

 conveys it to the place required. 



The beaver-houses are built of the same materials as their 

 dams, and are always proportioned in size to the number of inhabit- 



