Description of a Frame Uridine. 



125 



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It is estimated that a bridge of this kind may be built of one hun- 

 dred yards span, and possess all the strength necessary for common 

 use. Indeed, from tlie particular arrangement of the timbers, it is 

 evident tliat one built on this plan, can be carried to as great a span 

 as can be made of wood or iron. 



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