PoLTTEcnmc Association Proceedings. 819 



enabling it to withstand any accident or wear. Apart from the 

 fact that it cannot be burnt, or easily destroyed, it possesses the 

 recommendation of cheapness, costing about twenty per cent less 

 than other patterns. One of these cars has been in use since 1859, 

 and though it has been in one collision, it is pronounced now almost 

 as good as new. A small model car chair about three inches high, 

 dependent on the same principles of construction, was also exhi- 

 bited, which it was boldly stated would sustain a weight of two 

 hundred pounds. The covering of the car was to be metallic, and 

 of a very ingenious principle. The windows were to be suflSciently 

 long to permit the escape of passengers, should the doors in any 

 accident be closed. 



S USPENSION BRIDGES. 



The following paper was read by Charles Bender, civil engineer 

 (formerly assistant at the Polytechuical University at Karlsruhe, in 

 Germany): 



In the present day of long-span bridges, more particulary those 

 of suspension, across the wide rivers of this continent, it may not 

 be uninteresting to the civil engineer to trace the successive improve- 

 ments in their mode of construction, and to fix definitely the 

 claims of inventors and designers to such improvements as they 

 may be respectively entitled to. I am not aware that the subject 

 has been treated in this light before, and therefore, in view of its 

 importance, make no further apology for occupying your attention. 



I found in an old book the following sentence: 



*• The invention of the suspension bridges by Sir Samuel Brown 

 sprung from the sight of a spider's web hanging across the path of 

 the inventor, observed on a morning's walk, when his mind was occu- 

 pied with the idea of bridging the Tweed." 



The artificer of the web who really guided Sir Samuel Brown, 

 was the American engineer James Finlej^ of Fayette county, in the 

 State of Pennsylvania. He, in the year 1796, built the first regu- 

 lar suspension bridge across Jacob creek on the turnpike from 

 Uniontown to Greensburg, in the State of Pennsj'lvania. He 

 obtained the fii'st patent on this object from the Government of the 

 United States, and the book, " Treatise on Bridge Architecture, by 

 Thomas Pope," published in New York in the year 1811, spread 

 this ingenious invention over the whole world. Some English and 

 French authors, and even Pope, tried to diminish Finley's merits 

 by attributing this invention to the Chinese and Indians, but these 



