84 ESSAYS. 
the ordinary accidents that trees are heir to, and thus attain a 
longevity far transcending the habitual duration of the spe- 
cies. Is this view sustained by observation ? 
Before adducing the evidence which bears upon this ques- 
tion, it is necessary to inquire how the actual age of a tree 
may be ascertained. In most cases, — in all those trees which 
increase in diameter by annual concentric layers, — that is to 
say in nearly all trees except Palms and their allies, which for 
the present we may leave out of the question, the age may be 
directly ascertained by counting the annual rings on a cross 
section of the trunk. The record is sometimes illegible or 
nearly so, but it is perfectly authentic ; and when fairly de- 
ciphered, we may rely on its correctness.!. But the venerable 
trunks, whose ages we are most interested in determining, are 
rarely sound to the centre; and if they were, even the para- 
mount interests of science would seldom excuse the arboricide. 
This decisive test, therefore, can seldom be practically em- 
ployed, except in the case of comparatively young trees. The 
most remarkable recorded instance of its application is that 
of one of the old oaks at Bordza, in Samogitia (Russian Po- 
land) ; which, having been greatly injured by a conflagration, 
was felled in the year 1812, and seven hundred and ten 
concentric layers were distinctly counted on the transverse 
1 The discovery, or at least the first explicit announcement of the now 
familiar fact, that ordinary trees grow by annual layers, so that the ree- 
ord of their age is inscribed upon the section of the trunk, is generally 
attributed to Malpighi. But, probably, we should understand this cele- 
brated anatomist as merely giving a formal statement of what was already 
popularly known ; for so obvious a fact could scarcely have escaped no- 
tice. Professor Adrien de Jussieu, the present representative of that il- 
lustrious family, has, moreover, lately reproduced a passage in the “ Voy- 
age de Montaigne en Italie,’’ written in the year 1581, nearly fifty 
years before Malpighi was born, which proves this to have been the case. 
“ L’ouvrier, homme ingénieux et fameux a faire de beaux instruments de 
Mathématique, m’enseinga que tous les arbres portent autant de cercles qu’ils 
ont duré d’années, et me le fit voir dans tous ceux qwil avoit dans sa boutique, 
travaillant en bois. Et la partie qui regard le septentrion est plus étroite, 
et a les cercles plus serrés et plus denses que l'autre.” 
And now it appears that Leonardo da Vinci knew, and mentioned it — 
as well as phyllotaxis. (MSS. note in Dr. Gray’s handwriting.) 
