46 ANNUAL OF SCIENTIFIC DISCOVERY. 



in miiul, also, that by dispensini^ with stoves, 8 seats in each 

 ear are <^ainoil, ami, consequently, a train of 7 cars would 

 accommodate tlie same number of passenc^ers, which, with stoves, 

 wouUl require 8 cars. In short, tlie percentage upon the orig- 

 inal outlav would not compare to the annual expense of warming 

 cars upon the plans now in use. 



BRIDGES. 



T7ie East River Bridrje. — The plan of the East River Bridge, as 

 proposed by Mr. Roel)iing, has met with the ai)provalof tlie Board 

 of U. S. Engineers, ap))ointed to examine it, and of the Government, 

 and has been fully adoi)ted by the Board of Consulting Engineers, 

 consisting of Horatio Allen, Wm. J. MeAl|)ine, J. J. Serrell, Benj. 

 II. Lathrop, James P. Kirkwood, and ,] . Dutton Steele, who have 

 made to the Directors of the Biidge Company their final report, of 

 which the following is the substance : The plans, including foun- 

 dations, towers, and superstructure, have been laid before the 

 board by Mr. Roebling at various times between February 16 

 and April 26, and from him they have received the fullest infor- 

 mation touching all the details. Having completed the examina- 

 tion of the plans, and the investigation of the coml)inations and 

 proportions proposed, the board deemed it an appropriate part of 

 their duty to examine the structures of the same general charac- 

 ter erected by Mr. Roebling across the Monongahela and Alle- 

 ghany, at Pittsburgh, in 1846 and 1860; across the Niagara Falls 

 in 18o0, and across the Ohio, at Cincinnati, in 1860. They have 

 thus had an opportunity of learning the successive steps in bridge- 

 building, which, beginning with a span of 822 in 1854:, and one of 

 1,057 feet in 1867, all standing this day, are a practical demonstra- 

 tion of the soundness of the principles and proportions on which 

 these structures have been erected, and rendering unnecessary, at 

 least for spans of 1,000 feet, an}' other demonstration, and aflibrd- 

 ing the best source of information as to the practicability of tak- 

 ing another step in a span of 1,600 feet. The bridge proposed by 

 Mr. Roebling, a steel wire cable suspension bridge, 1,600 f(U!t 

 between the towers, 135 feet above the water, will be, in the 

 opinion of the board, a durable structure, of a strength sufficient 

 to withstand six times the strain to which it can under any cir- 

 cumstances be subjected ; that it will bear the action of the great- 

 est storm of which we have any knowleilge, and that the method 

 of joining the parts cannot be surpassed for simplicity and secu- 

 rity in the result. 



in the United States, the most remarkable suspension bridges 

 are Ellet's Wheeling bridge, over the Ohio, with a span of 1,010 

 feet; erected in 1848, and blown down in 1854. The Lewiston 

 bridge, 7 miles below Niagara Falls, built by E. ^V. Serrel, 

 spanned 1,040 feet. Roebling's bridge, at the FalN, spans 821 

 feet. McAlpine's new Niagara bridge has a span of 1,264 feet, 

 and the proposed bridge to connect New York and Brooklyn is to 

 have a span of 1,600 feet. 



