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tinguished ; whilst the pores in the chesnut require 
glasses to be seen distinctly. 
In consequence of the slow decay of the heart- 
wood of the oak and chesnut, these trees under 
favourable circumstances attain an age which can- 
not be much short of 1000 years. 
The beech, the ash, and the sycamore, most 
likely never live half as long. The duration of the 
apple*tree is not, probably, much more than 200 
years ; but the pear-tree, according to Mr. Knight, 
lives through double this period. Most of our best 
apples are supposed to have been introduced into 
Britain by a fruiterer of Henry the Eighth, and they 
are now in a state of old age. 
The oak and chesnut decay much sooner in a 
moist situation than in a dry and sandy soil ; and 
their timber is less firm. The sap vessels in such 
cases are more expanded, though less nourishing 
matter is carried into them ; and the general tex- 
ture of the formations of wood necessarily less 
firm. Such wood splits more easily, and is more 
liable to be affected by variations 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 
decomposition are checked by cold ; and at very 
low temperatures both animal and vegetable matters 
altogether resist putrefaction : and in the northern 
winter, not only vegetable life, but likewise vege- 
table decay must be at a stand. 
The antiputrescent quality of cold climates is 
fully illustrated in the instances of the rhinoceros 
