856 



THE POPULAR SCIENCE MONTHLY. 



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 ad- 

 dress 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 life- 

 time, if it could not all be guided by his 

 hand. The other papers were too numer- 

 ous to be even catalogued here. We men- 

 tion 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 Lon- 

 don, on " Arctic Explorations and Ethnol- 

 ogy " ; 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 plan- 

 ets ; of Professor Cook, of New Jersey, on 

 " Evidences of Coast Depression " ; of H. 

 Carvill Lewis, on " The Great Terminal Mo- 

 raine 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 eth- 

 nology. 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 Pro- 

 fessor W. B. Carpenter, of London, who 

 read a technical paper in the Microscopical 

 Section ; Dr. Valdemar Kovalevski, of Mos- 

 cow ; 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 Geogra- 

 phy, C. H. Hitchcock, of Hanover ; Biology, 

 W. J. Beale, of Lansing ; Histology and 

 Microscopy, J. D. Cox, of Cincinnati ; An- 

 thropology, 0. 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 mys- 

 tery 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 inter- 

 ruption 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 commence- 

 ment 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 tak- 

 ing a tree here and there, and always leav- 

 ing 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 thin- 

 nings. The competition between trees after 

 they reach their full height, at half their 

 full age, is for space to spread their heads ; 



