PEBIODIC PHENOMENA. 



When a man has learnt to take an interest in the varied operations of Nature which are everywhere being 

 carried on about him, and has acquired the habit of directing his attention to such matters, and keeping' 

 his senses always alive to any new information thereby afforded him, he has made himself almost independent 

 of outward circumstances. He has opened to himself a source of occupation and mental enjoyment, but little 

 affected by the ordinary vicissitudes of life.— Rev. Leonard Jknyns. 



ONSIDEUABLE 



interest attaches 

 to what may be 

 termed the "pe- 

 riodic phenomena" 

 of nature. Of 

 such a character 

 are the appearance 

 and disappearance 

 of animals, as 

 bats and badgers, which 

 conceal themselves 

 during the winter, and 

 pass through a period of hiber- 

 nation ; the change of dress at dif- 

 ferent seasons by the ermine, the 

 stoat, and their allies ; the coming 

 and going of the regular winter 

 or summer migratory birds ; the 

 retirement and hibernation of reptiles ; the move- 

 ments of certain fish up and down stream for the pur- 

 pose of spawning ; the appearance, transformations, 

 and disappearance of insects ; the leafing of trees ; 

 the flowering of plants ; the ripening of seeds ; the 

 fall of leaves ; — all these, and more, are worthy of 

 the attention of the lover of nature, and not beneath 

 the dignity of man. Linnteus constructed for him- 

 self a floral clock, in which the periods of time were 

 indicated by the opening or closing of certain flowers. 

 Gilbert White, and others since his time, not dis- 

 daining to be his disciples in such a work, con- 

 structed a calendar of which periodic phenomena 

 presented themselves to their notice. Humboldt 

 observes of the insects of the tropics, that they 

 everywhere follow a certain standard in the periods 

 at which they alternately arrive and disappear. At 

 fixed and invariable hours, in the same season, 

 and the same latitude, the air is peopled with new 

 inhabitants ; and in a zone where the barometer 

 becomes a clock (by the extreme regularity of the 

 horary variations of the atmospheric pressure), 

 No. 15. 



where everything proceeds with such admirable 

 regularity, we might guess blindfold the hour of 

 the day or night by the hum of the insects, and by 

 their stings, the pain of which differs according to 

 the nature of the poison that each insect deposits in 

 the wound. And the naturalist, whose quotation 

 heads this chapter, remarks, — "If an observant 

 naturalist, who had been long shut up in darkness 

 and solitude, without any measure of time, were 

 suddenly brought blindfolded into the open fields 

 and woods, he might gather with considerable accu- 

 racy from the various notes and noises which struck 

 his ears, what the exact period of the year might be." 



All such observations as we have alluded to are 

 easily made and as easily recorded, and of all, none 

 are of more interest than the migratory movements of 

 birds. We know that some visit us iu the spring and 

 abide during the summer ; others direct their flight 

 hither late in the autumn, and spend with us their 

 winter. But why this change, whence do they come, 

 and whither do they go ? We can partly answer 

 this question, but only partially, as the queries of 

 our correspondent H.E.A. (vol. I. pp. 71, 143), 

 still unanswered, testify. We may declare, in 

 general terms, that self-preservation, and the per- 

 petuation of the species, is the great moving cause. 

 That the journey is undertaken in search of food, or 

 a milder climate, or both, as a consequence the 

 former of the latter, or in search of suitable con- 

 ditions for rearing their young; yet there are many 

 special circumstances in which this answer is in- 

 applicable or insufficient. 



Knapp, in his " Journal of a Naturalist," a fitting 

 companion to White's " Selbome," remarks of the 

 Willow-wren: — "It is a difficult matter satis- 

 factorily to comprehend the object of these birds in 

 quitting another region, and passing into our island 

 These little creatures, the food of which is solely 

 insects, could assuredly find a sufficient supply of 

 such diet during the summer months in the woods 

 and thickets of those mild regions where they passed 



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