BRIDGES. 



BIODS to suit the strains imposed upon them, on account of the situation. The upper snr- 

 This variation is made necessary by the great face of the bottom chord and the lower sm 

 length of the span, which could not be reduced face of the top chord are curved therefore, iu 



stend of being straight, as is usual in tim- 

 ber bridges. The saving in dead weight 

 is one of the least advantages of this 

 arrangement, though that is not incon- 

 siderable. The covering of the trusses 

 will be of galvanized iron, having open- 

 ings between the braces, as shown in the 

 drawing. The principal braces r.ro so 

 wide apart as to permit a man to pasg 

 between them and within the covering 

 from one end to the other of the bridge. 



ELEVATION OF HALF SPAN, SU8QCJETTANNA E1UDGE. 



