286 Improvement in the Construction of Bridges, 6j*c. 



"If the bridge is of greater extent than can be included in one 

 span, it is simply rested on a thin pier, in the manner shown in 

 the elevation, without any other support. A covering of light 

 boarding, extending from the level of the road-way to the bottom 

 of the ribs, is spiked on the outside of the lattice-work to preserve 

 the timber. 



" The largest lattice-bridge which I met with, was constructed 

 by Mr. Robinson, on the Philadelphia and Reading Railroad. 

 It measures 1,100 feet in length. The lattice-frames, of which 

 it is formed, extend throughout the whole distance, between the 

 two abutments, without a break, and are supported on ten stone 

 piers, in the manner shown in the plates. 



" On the New York and Harlem Railway, there is a lattice- 

 bridge 736 feet in length, supported in the same manner, on four 

 stone piers." 



Since the above, there have been others finished, of much greater 

 extent and goodness, both under the direction of Moncure Robin- 

 son, Esq. and others. That at Richmond, Va., is so remarkable 

 for its magnitude and grandeur of effect, from the very bold and 

 rich landscape of that fine city, that its description may well be 

 here introduced, for it will convey both practical information and 

 rational entertainment.* 



The Railroad Bridge across James River, 



What is there yet to be done upon the face of the earth,, that 

 cannot be effected by the powers of the human mind, connected 

 with the ingenuity of the human hand ? The great elementary 

 principles of nature have long ago been mastered by the skill of 



* The following description of a bridge, constructed on the improvement of 

 Ithiel Town, as patented in 1835, it is fully believed will serve to show, not only 

 the confidence of one of the most eminent and experienced engineers of the Uni- 

 ted States, in the superior durability, economy, and strength of principle, as lately 

 improved by Mr. Town, but also the confidence which the public now feel in this 

 mode of construction, from this and many other railroad bridges now in use or 

 being erected. Among which is one on the Harlem Railroad, near New York; 

 four over the North and Mohawk rivers, near Troy ; one executed in a most splen- 

 did manner, over the Schuylkill, near Philadelphia, for the Baltimore Railroad; 

 two on the railroad from Petersburg to Raleigh, N. C. ; one at Tuscaloosa, Ala.; 

 one at Circleville, Ohio, &c. Reference to Mr. Town's advertisement in the 

 National Intelligencer, of August 5th, 11th, &c., and in the New York Weekly 

 Express, of the 4th of August, 1839, for terms and other particulars. — Keio Haven 

 Daily Herald, September I9th, 1838. 



