A correspondent says: " I suppose you have seen the statement of Mr. Charnay in ' The Ancient Cities of the New World' (page 260), denying the truth of the commonly received doctrine as to the annual formation of concentric circles in growing trees. My friend, Mr. Finck, of Cordova, Mexico, said to me many years ago, that he was satisfied that the rule would not hold good as to many tropical trees. If I am not mistaken, you have already somewhere in the pages of the Monthly discussed this question; but another article from your prolific brain would be most acceptable to some of your readers. I am frank to say that I have very little confidence in Charnay's archaeological theories, but his observations bearing upon this vexed question in vegetable physiology may be entitled to more credence, especially as they confirm, to some extent, the statements made by others of greater authority." [Possibly the answer to a- Boston correspondent in the last number of our magazine, in relation to the annual growths of the mammoth trees of California, will cover the question here. One simple consideration will show the absurdity of Charnay's calculation.

If his theory be correct, his trees in twenty years ought to be 40 feet thick ! - Ed. G. M].