286 Major-General Sir Howard Douglas on 



ness of the roads, and the want of bridges on large and rapid 

 rivers. To this cause may, in some measure, be attributed the 

 slow progress of civilization, of the cultivation of the arts and 

 sciences, and of the general diffusion of useful knowledge. A 

 conqueror did occasionally arise, inflamed with ambition, and 

 actuated by an enthusiasm for conquest, who carried in his 

 army men possessing a knowledge of all the science of the age 

 in which they lived. When a Greek or Roman general had 

 conquered a kingdom or a province, the first care of a conqueror 

 generally was, to introduce among the inhabitants a knowledge 

 of the arts then known ; and to this cause many of the ancient 

 European nations owe the introduction of the first rays of intel- 

 ligence by which they were enlightened. To retain possession 

 of conquests likely to be recovered by former rulers from intes- 

 tine commotions, or loss by the sudden incursions of neighbour- 

 ing tribes, a ready communication from one place to another, 

 and a rapid march of troops to quell any occasional insurrection, 

 or hostile attack, would form the first objects of the conqueror's 

 solicitude. Hence arose the Roman roads all over Europe, and 

 particularly in Britain, where traces of their remains yet traverse 

 the island from one extremity nearly to the other. If, in the 

 course of these roads, a large river crossed its direction, which in 

 floods was impassable by troops, then a magnificent bridge was 

 generally erected. There were thus constructed numerous 

 bridges in the course of a Roman itinerary. These have been of 

 great advantage, even in modern times, by affording facilities of 

 communication that would otherwise have been unattainable. 

 The methods of selecting lines, and of laying out of roads, have 

 been lately much improved ; therefore, the points where formerly 

 bridges had been erected, have been found to be injudicious; 

 and, consequently, in countries where manufactures and com- 

 merce have been introduced, it has been found indispensable to 

 change the line of direction, and to select new sites for bridges ; 

 though, in those countries that have slightly changed their con- 

 dition for centuries, the old Roman bridges have continued to 

 be used with considerable advantage^ both for the purposes of 

 commerce and of war. 



Next to the commodious situation of a bridge, its judicious 

 construction forms an important consideration. Arches and 



