382 
ANIMAL INTELLIGENCE. 
extent, and of the best form for the parpose. 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 heavers 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- 
- ion 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 
