As may naturally be supposed, the execution of these great works involved vast labour and anxiety. They were designed with much skill, and executed with equal ability. There were lock-gates to be constructed, principally of cast iron, sheathed with pine planking. Eight public road bridges crossed the line of the canal, which were made of cast iron, and swung horizontally. There were many mountain streams, swollen to torrents in winter, crossing under the canal, for which abundant water-way had to be provided, involving the construction of numerous culverts, tunnels, and under-bridges of large dimensions. There were also powerful sluices to let off the excess of water sent down from the adjacent mountains into the canal during winter. Three of these, of great size, high above the river Lochy, are constructed at a point where the canal is cut through the solid rock; and the sight of the mass of waters rushing down into the valley beneath, gives an impression of power which, once seen, is never forgotten. These great works were only brought to a completion after the labours of many years, during which the difficulties encountered in their construction had swelled the cost of the canal far beyond the original estimate. The rapid advances which had taken place in the interval in the prices of labour and materials also tended greatly to increase the expenses, and, after all, the canal, when completed and opened, was comparatively little used. This was doubtless owing, in a great measure, to the rapid changes which occurred in the system of navigation shortly after the projection of the undertaking. For these Telford was not responsible. He was called upon to make the canal, and he did so in the best manner. Engineers are not required to speculate as to the commercial value of the works they are required to construct; and there were circumstances connected with the scheme of the Caledonian Canal which removed it from the category of mere commercial adventures. It was a Government project, and it proved a failure as a paying concern. Hence it formed a prominent topic for discussion in the journals of the day; but the attacks made upon the Government because of their expenditure on the hapless undertaking were perhaps more felt by Telford, who was its engineer, than by all the ministers of state conjoined.