Page:Popular Science Monthly Volume 12.djvu/397

Rh But the facts appear to show that, in the uniformly warm climate of the tropics, rings are formed as regularly as in our own latitudes. True, in the tropics there are semi-annual changes from wet to dry, and from dry to wet, dependent on the earth's axial inclination; but, as the author remarks, even when there is absolutely no variation, the rings are formed. For instance, man-groves, growing on the muddy margins of tropical rivers, having from year's end to year's end uniform temperature and moisture, present clearly-defined rings of growth. Then the Cycads require several years to form one ring. The author's conclusion is, that "these circles have their origin in cycles of activity and repose, implanted in the constitution of the plant, which would continue to manifest themselves although there were no climatic variations. It is true," he adds, "that where seasonal variations exist, the successive stages of activity and rest are for obvious reasons synchronous with them, but they are not absolutely dependent on them. . . . The existence, therefore, of these markings in the ancient flora gives no information as to the existence at that time of seasons, and, so far as they are concerned, we are left free to adopt any conclusion as to the inclination of the earth's axis which may appear to us most reasonable."

Preservation of Wood under Water.—The effects of long-continued submergence in water on oak-wood are remarkable, and several instances are cited in the "Annales des Ponts et Chaussées," by M. Charrié-Marsaines, of oak being transformed so as very closely to resemble ebony. Thus, some pieces of oak taken in 1830 from an old bridge at Rouen, which had stood about 700 years, were found to resemble ebony, the modification being clue to the presence of peroxide of iron. M. Charrié-Marsaines himself having occasion, in constructing a discharge-sluice on the Rhine, to demolish an old military dam constructed in 1681 by Vauban, and based on a platform of oak, found this wood to have a dark color quite like that of ebony, and very great hardness, as was found on trying to cut it for use in the new works. The wood had then been 146 years in a soil constantly soaked by water, owing to the permeability of the layer of gravel here forming the bed of the Rhine.



the gas-works at Rahway, New Jersey, a simple and ingenious method of upward filtration through coke and "breeze" is in use for removing from the waste residuum the injurious products which otherwise would pollute the streams into which the waste might flow. This method is fully described, with accompanying sketch, by Mr. J. R. Shotwell in a letter to Prof. Spencer F. Baird, Fish Commissioner. Mr. Shotwell's communication is published in full in the Gas-Light Journal.

remarked, at the "Domestic Economy Congress," upon the mental inactivity of the army and navy, officers and men, in foreign parts. It was remarkable, he said, how little additional knowledge was brought home by these bodies from their visits to foreign countries. The speaker pictured "men sitting with their bands before them, or, what was worse, drinking brandy-and-water, who, if they had a slight knowledge of science given them at school, would have taken up some branch, and brought back valuable knowledge, instead of dyspepsia and discomfort."

on Lake Titicaca, Peru, toward the end of September, James Orton, late Professor of Natural History in Vassar College. The deceased was born in 1830, graduated from Williams College in 1855, and a few years later became a Congregational minister. He was an instructor in natural sciences in Rochester University in 1866, and in 1869 went to Vassar College. He thrice visited South America for the purpose of studying its natural history. First, in 1867, he led an expedition from Williams College across the continent by Quito, the Napo, and the Amazon. Again, in 1873, he made a journey across South America from Para up the Amazon to Lima and Lake Titicaca. He once more returned to the same fields of exploration last year. He was the author of several works, the best known being "The Andes and the Amazon" (1870), and "Comparative Zoology" (1875).

mate of the American whaling-bark A. Houghton, has arrived in New York, bearing with him a silver spoon with the arms of Sir John Franklin, which he obtained from an Esquimau at Whale Point, Hudson's Bay. From a party of Esquimaux, who camped during the winter of 1876-'77 near the winter quarters of the A. 