Engineers 



being well below the water-level usually about four feet 

 below. 



The lodges are roughly constructed of twigs, branches 

 and logs piled higgledy-piggledy and plastered freely 

 with mud. In outline these structures are nearly circular 

 and in elevation dome-shaped, the diameter being twice 

 the height as a rule. The inside of this dome-shaped 

 home measures about six feet in diameter and three feet 

 in height ; a generous store of grass forms the comfortable 

 lining. From time to time the lodges are enlarged ; the 

 wood of which they are constructed decays with the 

 passage of time and is removed from the inside by 

 the beavers and additions to compensate for its loss are 

 made on the outside. These lodges are mainly used as 

 winter homes ; in the summer most of the colony spend 

 their time swimming about in the neighbouring streams. 



The musquash or musk-rat, another North American 

 animal, is not unlike its relative the beaver in habits, 

 though as an engineer it is not nearly so ingenious. A 

 dweller by streams and ponds, the musquash, like the 

 beaver, is by instinct a burrower, and his burrows are much 

 more complicated than those of his cousin. In the bank 

 of some stream the musquash tunnels freely ; the mouth 

 of each tunnel opens below water ; many of them are very 

 long, often as much as sixty feet, and all of them slope 

 gently upwards to open into a common chamber, which v 

 forms the musk-rat's dwelling-room. 



The huts which these animals build are merely huge 

 piles of grass and other vegetation, from three to four feet 

 in height, to which the owners have access by burrowing 

 an opening into them. The outsides of these heaps of 

 vegetation are freely plastered with mud ; inside, the 

 musquash spends the colder months of the year, eating 

 away the walls of his residence meanwhile. A musquash 

 hut, then, is merely a storehouse of food, within which its 

 owner dwells so long as the food supply lasts. 



A third engineer is also, curiously enough, a native of 



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