FACULTIES OF THE MIND. 951 
templation of these, would be limited to-resemblance and 
succession. But as we begin to act upon the objects around 
us, and produce in them various changes, we acquire a 
knowledge of our own Power. When we see changes pro- 
duced independent of us, we consider it as the display of 
some other power. These changes, and the efforts which 
have preceded them, excite our ideas of cause and effect, 
means and ends. 
That the lower animals possess some notion of power and of 
cause and effect, may be inferred from various actions which 
they perform. ‘Thus, for example, we have seen the hood- 
ed crow (Corvus cornix,) i Zetland, when feeding on the 
testaceous mollusea, able to break some of the tenderer kinds 
by means of its bill, aided, in some cases, by beating them 
against a stone ; but as some of the larger shells, such as the 
buckie, (Buccinum undatum, ) and the wilk, cannot be bro- 
ken by such means, it employs another method, by which, 
im consequence of applying foreign power, it accomplishes its 
object. Seizing the shell with its claws, it-mounts up into 
the air, and then loosing its hold, causes the shell to fall 
among stones, (in preference to the sand, the water, or the 
soil on the ground,) that it may be broken and give easier 
access to the contained animal. Should the first attempt 
fail, a second or a third are tried, with this difference, that 
the crow rises higher in the a in order to increase the 
power of the fall, and more effectually remove the barrier 
to the contained morsel.; On such occasions, we have.seen 
a stronger bird remain an apparently inattentive -spectator 
of the process:of breaking the shell, -but.coming to the spot 
with astonishing keenness, when the efforts of its neghbour 
had-been successful, m order to share in the spoil *. Ani- 
* Pennant Brit. Zool. iv. p. 114, mentions similar operations performed 
by crows on mussels. 
