Having thus become an accomplished engineer, his wise old father sent him on a long tour, which lasted more than two years, in the course of which he inspected all the great works, both of the ancients and moderns, in Europe, and the more accessible parts of Africa and Asia. Returning home, the death of his father suddenly placed upon his shoulders the most extensive and difficult engineering business in Great Britain. But with such a training, under such a father, and inheriting so many traditional methods, he proved equal to the position, continued the great works begun by his father, and carried them on to successful completion. His father had already convinced the government that the old London Bridge could never be made sufficient for the traffic, or unobstructive to the navigation. A bridge has existed at this spot since the year 928, and some of the timbers of the original structure were still sound in 1824, when work upon the new bridge was begun. Thirty firms competed for the contract for building the new London Bridge, but it was awarded to the Rennies, under whose superintendence it was built. The bridge is nine hundred and twenty-eight feet in length, and has five arches. In this structure although utility was the first consideration, there in an elegant solidity of design which makes it pleasing and impressive in the highest degree. The rapid stream is as little obstructed as the circumstances admitted, and there does not appear to be in the bridge an atom of superfluous material. London Bridge is, I suppose, the most crowded thoroughfare in the world. Twenty-five thousand vehicles cross it daily, as well as countless multitudes of foot-passengers. So great is the throng, that there is a project now on foot to widen it. In 1831, when it was formally opened by King William IV., the great engineer was knighted, and he was in consequence ever after called Sir John Rennie. During the period of railroad building, Sir John Rennie constructed a great many remarkable works, particularly in Portugal and Sweden. We have lately heard much of the disappointment of young engineers whom the cessation in the construction of railroads has thrown out of business. Perhaps no profession suffered more from the dull times than this. Sir John Rennie explains the matter in his autobiography:-- "In 1844," he tells us, "the demand for engineering surveyors and assistants was very great. Engineering was considered to be the only profession where immense wealth and fame were to be acquired, and consequently everybody became engineers. It was not the question whether they were educated for it, or competent to undertake it, but simply whether any person chose to dub himself engineer; hence lawyers' clerks, surgeons' apprentices, merchants, tradesmen, officers in the army and navy, private gentlemen, left their professions and became engineers. The consequence was that innumerable blunders were made and vast sums of money were recklessly expended."