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more easily, and is more liable to be affected by varia- 

 tions in the state of .the atmosphere. 



The same trees, in general, are much longer lived 

 In the northern than in the southern climates. The 

 reason seems to be, that all fermentation and decom- 

 position are checked by cold; and at very low temper- 

 atures both animal and vegetable matters altogether 

 resist putrefaction: and in the northern winter, not 

 only vegetable life, but likewise vegetable decay must 

 be at a stand. 



The antiputrescent quality of cold climates is ful- 

 ly illustrated in the instances of the rhinoceros and 

 mammoth lately found in Siberia, entire beneath the 

 frozen soil, in which they must probably have existed 

 from the time of the deluge. I examined a part of the 

 skin of the mammoth, sent to this country, on which 

 there was some coarse hair; it had all the chemical 

 characters of recently dried skin. 



Trees that grow in situations much exposed to 

 winds, have harder and firmer wood than such as are 

 considerably sheltered. The dense sap is determined 

 by the agitation of the smaller brances to the trunk 

 and large branches; where the new alburnum formed 

 is consequently thick and firm. Such trees abound in 

 the crooked limbs fitted for forming knee-timber, 

 which is necessary for joining the decks and sides of 

 ships. The gales in elevated situations gradually act, 

 so as to give the tree the form best calculated to resist 

 tneir effects. And the mountain oak rises robust and 

 sturdy; fixed firmly in the soil, and able to oppose the 

 full force of the tempest. 



