382 ANIMAL INTELLIGENCE. 



extent, and of the best form for the purpose. There is 

 thus shown much too great a concurrence of engineering 

 principles to the attainment of one object to admit of our 

 attributing the facts to accident. On this structure Mr. 

 Morgan observes : — 



The crests of these dams where they cross the canals are 

 depressed, or worn down, in the centre, by the constant pas- 

 sage of beavers over them while going to and fro and dragging 

 their cuttings. This canal with its adjuncts of dams and 

 its manifest objects is a remarkable work, transcending very 

 much the ordinary estimates of the intelligence of the beaver. 

 It served to bring the occupants of the pond into easy con- 

 nection by water with the trees that supplied them with food, 

 as well as to relieve them from the tedious and perhaps im- 

 possible task of transporting their cuttings 500 feet over uneven 

 ground unassisted by any descent. 



Again, in another case, also sketched by Mr. Morgan, 

 another device is resorted to, and one which, having re- 

 ference to the particular circumstances of the case, is the 

 best that could have been adopted. Here the canal, 

 proceeding from the pond to the woodland 150 feet dis- 

 tant, encounters at the woodland a rising slope covered 

 with hard wood. Thereupon the canal bifurcates, and the 

 two diverging branches or prongs are carried in opposite 

 directions along the base of the woodland rise, one for a 

 distance of 100 and the other for 115 feet. The level 

 being throughout the same, the water from the pond sup- 

 plies the two branch-canals as well as the trunk. Both 

 branches end with abrupt vertical faces. Now the object 

 of these branches is sufficiently apparent : — 



After the rising ground, and with it the hard wood trees, 

 were reached at the point where it branches, there was no 

 very urgent necessity for the branches. But their construc- 

 tion along the base of the high ground gave them a frontage 

 upon the canal of 215 feet of hard- wood lands, thus affording to 

 them, along this extended line, the great advantages of water 

 transportation for their cuttings. 



One more proof of engineering purpose in the con- 

 struction of canals will be sufficient to place beyond all. 



