Page:Popular Science Monthly Volume 20.djvu/147

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pressed spine than the ancient form. In another paper, Professor Morse, after referring to the fact that, although worked shells were not uncommon in the shell-heaps of Florida and California, none had been found in the New England and Japanese shell heaps, exhibited specimens of the large beach-cockle (Lunatia) from Marblehead, Massachusetts, which had unmistakably been worked by cutting out a part of the outer whorl near the suture. To show that this could not have been artificially broken, he exhibited naturally broken shells of the same species, both ancient and recent, in which the fractures were essentially unlike those of the worked shells.


Who were the Mound-Builders?—Dr. W. De Haas, after a careful examination of the supposed connection between the "mound-builders" and the ancient races of Mexico, has come to the conclusion that it does not exist. He considers that the former people were but little advanced beyond the modern Indians, but that they were different. In the discussion that followed the reading of Dr. De Haas's paper in the American Association, Judge Henderson objected to the use of the term "mound-builder," as one that conveyed a false idea. There is no evidence, he said, which will justify us in separating the ancient and more modern races, not a single feature peculiar to the so-called mound-builders. The speaker had started out in the study of American archæology with the impression that these people were distinct and separate from the Indians, but he had been compelled by the force of facts to relinquish the theory. It was improper to talk about these people as mysterious, for they were no more mysterious than the Shawnees, the Natchez, the Tensas, and other tribes. The cloth found in their works was like that made by every tribe from the Lakes to the Gulf, even less fine than some, and their pottery was no better. In short, the speaker said, in his judgment, the mound-builders were the ancestors of the Indians.


M. Trouvé's Electric Canoe.—"La Nature" gives the details of a series of experiments made upon the Seine, at Paris, in the latter days of May, with the electric canoe and motor invented by M. G. Trouvé. The motor is composed of an improved Siemens coil, which acts through a Vaucasson chain and a Galle chain upon a three-bladed screw fitted into an opening cut out of the rudder to receive it. It is fixed to the upper part of the rudder, so that it, as well as the screw, follows all its movements. The motor employed in the experiments was composed of two coils, and, with its accessories, did not weigh more than five kilogrammes (twelve and a half pounds). It was placed in the stern of a canoe, the Telephone, which measured seventeen feet ten inches by three feet ten inches, and weighed one hundred and eighty pounds. Two cup batteries of bichromate of potassa, composed of six elements each, and weighing together sixty pounds, were placed in the middle of the canoe. They were connected with the motors by two cords, which served at the same time as envelopes for the conducting wires and as tiller-ropes, and which were furnished with appurtenances for applying or shutting off the current at will. The motor is independent, and can be applied to any boat. The first experiments were made on the 26th of May, when the boat was worked for about forty-five minutes by M. Trouvé and M. Tissandier, in the afternoon, and by M. Trouvé and others for about the same time in the evening. A third experiment was made on the 31st of May, in the presence of M. G. Berger, commissioner-general of the Universal Electrical Exposition, M. A. Breguet, of the "Revue Scientifique," M. Hospitalier, M. Fricéro, of the Russian navy, and others. The Telephone, with three persons in it, easily went up the Seine six times for a distance of two hundred metres, or six hundred and fifty feet, at the rate of one metre in a second, and descended at the rate of two and a half metres in a second. Other experiments were made on the 2d of June, in presence of the Russian Admiral Likhatchof and a number of spectators interested in science or navigation. These experiments recall a similar attempt made on the Neva in 1839, by Jacobi. He used on the occasion two Grove batteries, each composed of sixty-four couples of zinc and platinum, and presenting a surface of sixteen square feet. The