hensive review which we publish in the present number of "The Popular Science Monthly," of the "Progress of American Mineralogy." Dr. Asa Gray gave an address on the "History of the Study of the North American Flora," and expressed the hope that the work of examination and classification might be completed in his lifetime, if it could not all be guided by his hand. The other papers were too numerous to be even catalogued here. We mention only a few, which seem to be of general importance or interest. They are those of Professor Mason, unfolding a scheme of anthropology; of Dr. John Rae, of London, on "Arctic Explorations and Ethnology"; of Commander Bartlett, on "The Gulf Stream"; of Mr. Franklin B. Hough, on "Plantations of the Eucalyptus"; of the Rev. Dr. Houghton, of Dublin, embodying a new theory of the evolution of the planets; of Professor Cook, of New Jersey, on "Evidences of Coast Depression"; of H. Carvill Lewis, on "The Great Terminal Moraine across Pennsylvania"; of Professor Newberry, on "The History of Plant-Life in America"; of the Hon. Horatio Hale, of Clinton, Ontario, on "Indian Migrations as evidenced by their Language"; and of Mrs. Erminie Smith and Miss Alice C. Fletcher, on topics relating to Indian ethnology. Excursions were made to Quebec, Ottawa, and other places. Several visitors of distinction were present from abroad. Among them, besides those already named in connection with their papers, were Professor W. B. Carpenter, of London, who read a technical paper in the Microscopical Section; Dr. Valdemar Kovalevski, of Moscow; Dr. Koenig, of Paris; Mr. Fitzgerald, of Dublin; and D. Szabo, of Buda-Pesth, Hungary, who had a paper in the Chemical Section. A good financial exhibit was made, with the announcement of generous special gifts. A memorial to Professor Rogers was determined upon. The Association decided to hold its meeting for 1883 at Minneapolis, Minnesota. The following officers were chosen: President, Professor C. A. Young, of Princeton; vice-presidents of sections: Mathematics and Astronomy, W. A. Rogers, of Cambridge; Physics, H. A. Rowland, of Baltimore; Chemistry, E. W. Morley, of Cleveland; Mechanical Science, De Valson Wood, of Hoboken; Geology and Geography, C. H. Hitchcock, of Hanover; Biology, W. J. Beale, of Lansing; Histology and Microscopy, J. D. Cox, of Cincinnati; Anthropology, O. T. Mason, of Washington; Economical Science and Statistics, F. B. Hough, of Lowville. The purpose of the British Association to hold its meeting for 1884 in Montreal was announced.
Scientific Forestry.—There is no mystery in the scientific cultivation of forests, so far as concerns the tillage of the crop. All that is needed is to observe the action of nature in the forest, and follow it, or utilize it advantageously, when that can be done. The object of the cultivation should be to obtain the utmost possible advantage from the soil by keeping it always covered with a growth of trees; and, when the trees arrive at maturity, to remove them in such a manner that the smallest possible interruption may be caused to the productive work of nature. When the time has come for the removal of the timber, the ground should on no account be anywhere all cleared of trees at once; but a commencement should be made by felling a tree here and there, and so breaking the thick cover of the forest as to allow sufficient light and air to reach the ground, and cause the seed which has fallen to germinate. In this w r ay about one fifth of the mature trees should be removed every five or six years, never by making large gaps in the cover, but taking a tree here and there, and always leaving the finest and most vigorous trees till the last, so that in about thirty years the whole of the old trees will be cleared off, and a new forest established in their place. Thus the seeding of the wood will be effected by the agency of the finest trees, which will be themselves all the while increasing in bulk, and the productive power of the soil will be utilized to the fullest possible amount. It is not only in the removal of the timber and the reproduction of the forest that we ought to study the action of nature, but it is equally necessary that we should do so in the felling for improving the growing crop, or, as it is commonly called, the thinnings. The competition between trees after they reach their full height, at half their full age, is for space to spread their heads;
