The many differences of opinion that even eminent men are presumed to hold in regard to the character of the so-called annual rings of trees, would be readily reconciled if a little thought were given to the manner in which wood is formed as the trunk is enlarged. This is accomplished by the birth of new cells, which proceed laterally from the old ones. The new course of cells take their place around the mother cells, and form a thin layer over them, just as if a sheet of writing-paper might be wrapped around another. These in a few days again become mother cells, and another course is produced. This continues during the short time devoted to growth, perhaps a dozen times, and the mass of new wood, known as the new annual layer, is really made up of a dozen fine layers so small that the concentric lines are only visible by means of a powerful microscope. Now the size of these cells depends on the amount of material at command. The original mother cell that starts the annual growth, has had the advantage of the best opportunities for stored nutrition, every successive addition is weaker and weaker, until the last growths of the season are very small.

It is because they are so small and packed close together that we can readily see where they end and thus detect the extent of the annual layer even in old trees. Now a tree may be in a position to have command of a superior stock of nutrition, and the cells are in a condition to avail themselves of the advantages, especially if the cells are naturally of a large size, as they are in some trees. In the European silver linden, for instance, the cells are one-fourth larger than they are in the common American linden; and in this and similar trees, a number of light rings can usually be traced in the annual increment. The same can often be seen in vigorous specimens of the cottonwood. But plainly as these lines may be seen, the experienced investigator can rarely be mistaken on the last line made during the growing season, and is able to tell how many years the tree has been growing on the spot where it stands. There is nothing more certain than that in the hand of an expert the age of a tree can be determined by its annual growths. These remarks are suggested by A. H. Keane's review of Charnay's "Ancient Cities of the New World " in the Academy for May 28th last.

The reviewer gives the author some well-deserved criticisms on various ethnological absurdities, but believes his science deserves more praise. But the science that refers to tree growth is also somewhat lame. He believes he has settled the "great tree question" by showing that in the mahogany and other local species the rings correspond to months and not to years. "In a twig eighteen months old he counted eighteen circles." He cut down a tree twenty-two years ago, and from this stump grew a tree which, cut down, showed 230 rings - one in a month, or even less. It would have been more profitable if the whole diameter of the twenty-two-year-old tree had been given. One can generally tell the age of a tree by its size. The increase of any tree ranges between one-eighth of an inch to one inch - the latter being extremely rare. About one'fourth inch a year is the average increase in diameter with healthy maturing trees. It is said that Waldeck estimated a ruin at 2,000 years, and Lirainzar at 1,700. Allowing but one-eighth inch growth - one-quarter inch diameter - a very weak growth for such a climate, the tree ought to have been forty feet wide.

No doubt, as Keane says, the circles counted were not annual ones; but as Keane does not say, there are annual rings for all".

[The above from the pen of the Editor of this Magazine appeared in the Independent of October 13, and is given here on account of the generous appreciation of a correspondent on account of the many public comments on Charnay's wonderful statements.--Ed. G. M].