Page:Popular Science Monthly Volume 26.djvu/298

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286
THE POPULAR SCIENCE MONTHLY

a wreath was placed at its feet. M. Tresca made the memorial address, and claimed for Papin the distinction of having been the inventor of the first steam-engine. Excursions were made to various places of interest, among them the strata of Thenay, where Abbé Bourgeois thinks he has discovered relics of tertiary man, and the Celtic caverns of Troô.

 

Discussions at the Electrical Conference. —An Electrical Conference sat in Philadelphia, in connection with the Electrical Exhibition, during the second week in September, and was attended by about one hundred and seventy-five American and foreign delegates. Professor Simon Newcomb opened the session with an address of welcome, after which the President of the Conference, Professor Henry A. Rowland, presented in his official address the subjects of the interdependence of applied and pure science, some of the questions still open in electrical science, and the need of more careful training in the theory of electricity in technical schools. The meetings of the Conference were continued, with discussions of the best methods of extending our knowledge of atmospheric electricity and earth-currents, and any possible relation that may exist between them and the weather, by Professor Abbe; the question of the establishment of a Bureau of Physical Standards, under the supervision of the Government, by Professor Snyder and other members of the Conference; the theory of the dynamo-electric machine, by Professor Rowland, with remarks by Professor Fitzgerald, of Dublin, and Professor Silvanus P. Thompson; the electrical transmission of energy, by Professor Nipher, of Washington University, St. Louis; storage-batteries, by Mr. W. H. Preece and Professor Dewar; and long-distance telephony. On the last subject Mr. T. D. Lockwood mentioned earth-currents, atmospheric electricity, imperfect contacts, and leakage from other lines, together with electro-static and electro-dynamic induction, as causes of the noises on telephone lines. Long lines are more subject to these troubles than short ones, and north and south lines than east and west ones. Sometimes one end of the lino will be noisy and the other end quiet, as between Chicago and Milwaukee, where it is quiet at the Chicago end and noisy at Milwaukee. Lines subject to nearly uniform leakage are more quiet than well-insulated lines, lines near the sea than inland ones, and lines of small wire than lines of large wire. Many of the sources of disturbance may be got rid of by providing a metallic return-circuit, hung parallel to the first circuit and similarly to it. When a long air-line ends in a short underground cable, the person at the end of the cable can make himself heard, while the person at the end of the long line can not. Captain O. E. Michaelis recommended the study of iron, copper, brass, etc.—the metals used in structures—by electrical or magnetic methods— with a view to finding means of discovering defects and weaknesses. On the electrical protection of houses, Professor Rowland spoke well of the conductors enveloping the house as if they were a cage: thus, it is well to have the rods run down the four corners of the house and across the angles of the roof, joining at the top, so as to form the skeleton of the cage. Additional rods may also be run down the sides of the house. The rods must be well grounded, otherwise they will be worse than useless. Twisted rods are not recommended. Small rods, bearing points, should rise from the main rods at different points on the roof.

 

The Association of Official Chemists.— An Association of Official Chemists of the United States was organized during the meeting of the American Association. Chemists of the Department of Agriculture, State agricultural societies, and boards of official control, are eligible to membership in the Association, and each of the organizations thus represented is entitled to one vote on all matters on which the society may ballot, while other chemists are invited to attend the meetings and take part in the discussions, without having the right to vote. Three standing committees were appointed —on the determination of phosphoric acid, nitrogen, and potash—who will distribute samples for comparative work, and report the results at the annual or at special meetings. The following officers of the Association were elected: President, Professor S. W, Johnson, of Connecticut; Vice-President, Professor H. C. White, of Georgia;