148 TRAKSACTIONS OF THE [MAY 23, 



THE DEVELOPMENT OF BRIDGE-CONSTRUCTION, AVITH NOTICES 

 OF SOME REMARKABLE HISTORIC BRIDGES. 



(Illustrated with the magic lantern.) 



In works of engineering generally, unlike those connected 

 with the fine arts, there is little to be learned from the ancients. 

 We are surrounded on all sides by structures of a purely en- 

 gineering character, which could only have been devised and 

 executed in modern times, and for which antique models do not 

 exist. There are certain elements, however, of these structures 

 which belong to all ages, since they are but the practical appli- 

 cations of simple mechanical laws in which boldness of con- 

 ception and design, simplicity and taste in construction, and 

 perfect adaptability to their uses and objects, exhibit the intel- 

 lectual condition of the people by whom such structures have 

 been erected. 



It may be said that properly constructed lines of land travel 

 are botli causes and effects of civilization. The common road 

 and the railway, pushing out beyond the boundaries of populous 

 districts or penetrating uninhabited wildernesses, are sure to be 

 followed by an advancing tide of emigration, while the introduc- 

 tion and maintenance of thoroughfares, more complete and per- 

 manent in their construction than was at first practicable, is an 

 indication of increasing thrift, culture, and refinement on the 

 part of the people. 



The famous engineer, Telford, who constructed many hun- 

 dred miles of good turnpike roads in England and Scotland 

 under special acts of Parliament, expressed the opinion or 

 belief that these roads had advanced the communities of the 

 districts through whicli they passed, one hundred years in civili- 

 zation. 



The construction of a line of land travel involves, of course, 

 numerous bridges, rude and cheap in primitive times, but ex- 

 hibiting elements of a more permanent character and more 

 pleasing architectural features as a country advances in wealth 

 and education. There are few architectural structures which 

 more truly indicate intellectual cultivation and general pros- 



