ADDRESS. Ixxxi 



suflfico for a population of seven millions, supplied at the rate at which the 

 prejout population of London is supplied. This water was conveyed to Rome 

 hy nine aqueducts ; and iu later years tho supply was increased by the con- 

 sLriiction of five more aqueducts. Three of the old aqueducts have sufficed 

 to supply tho wants of the city in modern times. These aqueducts of Rome 

 are to be numbered among her grandest engineering works *. Time will not 

 admit of my saying any thing about her harbour works and bridges, her basi- 

 licas and baths, and numerous other works in Europe, in Asia, and in Africa. 

 Not only were these works executed in a substantial and perfect manner, but 

 they were maintained by an efficient staff of men divided into bodies, each 

 having their special duties to perform. The highest offi cers of state superin- 

 tended the construction of works, were proud to have their names associated 

 with them, and constructed extensive works at their own expense. 



Progress in Europe stopped with the fall of the Roman Empire. In the 

 fourth and succeeding centuries the barbarian hordes of Western Asia, people 

 who felt no want of roads and bridges, swept over Europe to plunder and 

 destroy. 



With the seventh century began the rise of the Mohammedan power, and 

 a partial return to conditions apparently more favourable to the progress of 

 industrial art, when widespread lands were again united under the sway of 

 powerful rulerst. Science owes much to Arab scholars, who kept and handed 

 on to us the knowledge acquired so slowly in ancient times, and much of 

 which would have been lost but for them. Still, few useful works remain to 

 mark the supremacy of the Mohammedan power at all comparable to those 

 of the age which preceded its rise. 



A great building age began in Europe in the tenth century, and lasted 

 through the thirteenth. It was during this period that these great ecclesias- 

 tical buildings were erected, which are not more remarkable for artistic ex- 

 cellence than for boldness in design. 



While the building of cathedrals progressed on aU sides in Europe, works 

 of a utilitarian character, which concern the engineer, did not receive much 

 encouragement, excepting perhaps in Italy. 



From the twelfth to the thirteenth centuries, with the revival of the arts 

 and sciences in the Italian republics, many important works were undertaken 

 for the improvement of the rivers and harbours of Italy. In 1481 canal-locks 

 were first used ; and some of the earliest of which we have record were 

 erected by Leonardo da Vinci, who would be remembered as a skilful en- 

 gineer had he not left other greater and more attractive works to claim the 

 homage of posterity. 



* Total length 250 miles ; 50 on arches, 200 undergrouncl. 



t " Under the last of the house of Ommiyah (750 a.d.) one command was obeyed 

 almost along the whole diameter of the known world, from the banks of the Sihon to tho 

 utmost promontory of Portugal." — Hallam's Middle Ages, vol. ii. p. 120, 2nd edit. 

 1875. " / 



