...and by counting their number, it will give the term of its duration. It appears that the sap-vessels, under the bark, which are in a soft spungy state during...annual additions are in general clearly discernible. In looking at the end of a piece of timber, or the arm of a tree newly cut, the parts within two or...

...observer of nature. It appears that the sap-vessels, just under the bark, which are in a soft, spongy state during the summer, harden in the winter, and...circle of vessels, pushing the bark outwards ; and this, in its turn, changes into the close-grained proper wood of the tree. Thus the whole is enlarged,...

...the term of its duration. It appears that the sap-vessels, under the bark, which are in a soft spongy state during the summer, harden in the winter, and...annual additions are in general clearly discernible. In looking at the end of a piece of timber, or the arm of a tree newly cut, the parts within two or...

...besides eyes seems needful to constitute an accurate observer of nature. It appears that the sap vessels, just under the bark, which are in a soft spungy state...rises in another circle of vessels, pushing the bark outward ; and, in its turn, changes into the close-grained proper wood of the tree. Thus the whole...

...and spongy in the summer, and harden and get to be firm wood in the winter : when spring comes again, fresh sap rises in another circle of vessels, pushing the bark outwards ; and this in turn hardens again in the winter, and so it goes on year after year, forming new circles until...