312 



SCIENCE. 



[Vol. XIII. No. 325 



CONGRESS OF ELJECT-RICIANS AT^THE PARIS 

 EXHIEilTIO.N* 

 By a ministerial decree dated July i6 last, it was decided to hold 

 an international congress of electricians at Paris during the exhibi- 

 tion. All the arrangements are now completed, and the congress 

 will open on Aug. 24, and remain open eight days. The following, 

 relative to this congress, has been issued to those likely to be in- 

 terested in its work : " The International Congress of Electricians, 

 which met at Paris in 18S1, marks an important date in the history 

 of electricity. The consecration of practical unities has had on the 

 development of science and industry an influence the significance 

 of which cannot be exaggerated. The extreme rapidity and facility 

 with which the decisions of the congress were accepted, in the study 

 and in the laboratory, demonstrate their utility. The International 



AN ELECTRIC DRAWBRIDGE. 



One of the latest applications of the electric motor which has 

 excited much interest, not only from its novelty, but also the excel- 

 lence of its operation, is that of the turning of drawbridges. This 

 is a matter to which a good deal of attention has been given both 

 by bridge and electrical men ; but it is not until recently that the 

 motor for this purpose has supplanted steam, and the slow, labori- 

 ous method of the long lever worked by three men. 



One installation, the details of which are shown in the accom- 

 panying cuts, has recently been made at Bridgeport, Conn., by the 

 New England Electric Supply Company. The drawbridge, which 

 is 180 feet long, 60 feet wide, and weighs 320 tons, was formerly 

 operated by three men ; but this method was found to be open to 



ELECTRIC DRAWBRIDGE AT BRIDGEPORT, COXX. 



Exhibition of 1889 offers a natural occasion of continuing and 

 completing the work of 1881 ; not that the new congress may have 

 to treat of problems of so general and elevated an order, but many 

 questions still remain on which an understanding, or at least an 

 exchange of views, is desirable. In the programme which it has 

 prepared, the organizing committee has not been pretentious 

 enough to indicate them all, and still less to impose limits to the 

 field of activity of the congress : it has simply wished to call atten- 

 tion to those which appeared to it of more general and more im- 

 mediate interest. We believe we respond to the unanimous feeling 

 of electricians in placing the following questions foremost : practi- 

 cal measure of electrical energy in all its forms ; measure of the 

 current in absolute value with standard of easy reproduction ; 

 electricity meters for continuous and alternating currents ; practi- 

 cal evaluation of the lighting ; definition of the constant quantities 

 of a machine from a commercial point of view ; etc. We hope that 

 the savanis a.nd manufacturers who have contributed to the progress 

 and application of electricity will readily respond to our appeal, and 

 contribute to give this meeting the importance and authority of 

 that which preceded it." 



serious objections, and attended by considerable expense, as it 

 necessitated the constant attendance of the men, and, under the 

 most favorable circumstances, it took six minutes to open and close 

 the draw, which caused a jam on both sides, and seriously inter- 

 fered with the traffic. 



The problem of applying electricity as a motive power has been 

 successfully worked out to the satisfaction of both the city officials 

 and the bridge-builders. The draw can be opened and closed in 

 two minutes, and the expense is limited to the hiring of one man 

 and the monthly charge of the Electric Light Company, by which a 

 considerable saving is effected. The details of the construction 

 are as follows : — 



The current is conducted to the motor through two submarine 

 cables, the core being equal to No. 4 B. & S. copper wire, which are 

 protected from lightning by two Thomson-Houston lightning- 

 arresters. The shore ends are connected to the incandescent- 

 lighting current of the Bridgeport Electric Light Company by a 

 double-pole switch, so that the current may be shut off at the 

 pleasure of the draw-tender. The other ends are connected to 

 vertical stationary posts, which are carefully insulated from the 



