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" time of the singing of birds is come," that they 

 may now safely return and join their notes with the 

 woodland choir. A mere change of temperature does 

 not amount to the full estimate required here, for how 

 can that penetrate the clay cearment of the Canada 

 jumping mouse, and other animals, surrounded by and 

 deeply buried in non-conducting media, as the marmot 

 and others. The cause that rouses from torpidity is 

 doubtless an electric one, and in the migration of birds 

 the same cause is in full operative influence. 



We certainly know not what instinct means, and there- 

 fore cannot give its portraiture. In many things it is 

 the image of reason, and its counterpart. In some 

 cases it even transcends the powers of reason ; for it 

 occasionally seems to catch a glimpse of futurity, and 

 be its prophet. Still its mechanism is limited ; while 

 reason has capabilities endowed with infinite expansion, 

 "grows with our growth, and strengthens with our 

 strength." Nor can we describe what may be the 

 majesty of its powers, when we shall have " shuffled 

 off this mortal coil," and it is unshackled by resistance, 

 its vision unclouded. 



" Creation needs no new fiat ; but the succession of 

 events, throughout all her works, depends on laws 

 which are unerring, because they are not imposed by 

 any thing from without, but are the very nature and 

 constitution of the beings that appear to obey them. 

 It is this which makes nature so wonderful ; which so 

 stamps upon it the impress of an Almighty Creator: 

 its parts and phenomena are millions; the primary 

 Power that puts all in motion is but one." 



" Yea the stork in the heavens knoweth her ap- 

 pointed time ; and the turtle, and the crane, and the 

 swallow, observe the time of their coming." * 

 * Jeremiah, viii. 7. 



