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 in- ventor of the first steam-engine. Excur- sions were made to various places of inter- est, among them the strata of Thenay, where Abbe Bourgeois thinks he has discovered relics of tertiary man, and the Celtic cav- erns of TroO.

Discussions at the Electrical Conference.

— An Electrical Conference sat in Philadel- phia, in connection with the Electrical Ex- hibition, during the second week in Septem- ber, and was attended by about one hundred and seventy-five American and foreign dele- gates. Professor Simon Newcomb opened the session with an address of welcome, aft- er which the President of the Conference, Professor Henry A. Rowland, presented in his official address the subjects of the in- terdependence of applied and pure science, some of the questions still open in electrical science, and the need of more careful train- ing 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 be- tween 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 Confer- ence ; the theory of the dynamo-electric ma- chine, by Professor Rowland, with remarks by Professor Fitzgerald, of Dublin, and Pro- fessor Silvanus P. Thompson ; the electrical transmission of energy, by Professor Nipher, of Washington University, St. Louis ; stor- age-batteries, by Mr. TV. H. Preece and Pro- fessor Dcwar; and long-distance telephony. On the last subject Mr. T. D. Lockwood mentioned earth-currents, atmospheric elec- tricity, 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 tlie 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-iusulated 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 metal- lic 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 0. E. Michaclis recommended the study of iron, copper, brass, etc. — the metals used in struct- ures — 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 cor- ners 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, otherwi-e 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.

Tbe Association of Oificial Chemists. —

An Association of Official Chemists of the United States was organized during the meeting of the American Association. Chem- ists 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 discus- sions, 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 meet- ings. The following officers of the Asso- ciation were elected : President, Professor S. W, Johnson, of Connecticut ; Vice-Presi- dent, Professor II. C. White, of Georgia ;

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