316 NATURAL HISTORY READER. 



to distinguish daylight from darkness, and for this purpose 

 these microscopic dots may suffice ; but as regards any other 

 and more specific visual powers, he is practically blind. 



John Burroughs. 



FOREST ENGINEERS. 



1. The beaver is at once an engineer, a carpenter, and 

 a mason. As we shall see, it prepares the place for its 

 habitations with all the skill of an experienced engineer, 

 and in its building it uses the materials and methods of both 

 the carpenter and mason. The beaver was once an inhabi- 

 tant of all the northern part of the "United States, but is 

 now met with only in the remote parts of the Northwest 

 and in Canada. Its nearest relation now among us is the 

 musquash, or musk-rat, which ought to be called the 

 musk-beaver, as it is no rat at all. And if you want to 

 know about the beaver, the best thing you can do is to ob- 

 serve the habits of the musquash. His house is very much 

 like the beaver's house, only smaller, and he can do almost 

 everything that his cousin does, except make clams and 

 canals. And even the beaver does not build those, except 

 when they are really needed, as I shall show. 



2. A beaver is two or three times as large as a musquash ; 

 indeed, sometimes he is as heavy as a stout boy, weighing 

 seventy or eighty pounds. His tail is flattened, like that 

 of the musquash, only much more so, and the edges are 

 horizontal instead of vertical. It was once thought that 

 ho used this broad, flat tail as a spade or trowel, but this is 

 not now generally believed. At any rate, the tail is the 

 most curious part of the animal, it is so long and large, 

 and covered with rough scales instead of fur. The beaver 

 sculls his way with it in the water, as you can scull a boat 



