The width of the Moer-Vater, or Lieve, at this point, was ten hundred and eighty yards, and spanned by an old bridge, the stone piers of which were very near together, having been built by the emperor Hadrian in the early part of the second century. The rise of the tide in the North Sea, close at hand, was from fifteen to eighteen feet, thus producing a current almost as rapid as that of the Mersey at Liverpool. The commissioners determined to utilize this force, in preference to the erection of expensive steam works at the mouth of the mine. A plan was submitted by Cyrus W. Field, and at once adopted. Turbine wheels were built, covering the space betwixt each arch, movable, and adapted to the rise and fall of the tide. Gates were also constructed between each arch, and a head of water, ranging from ten to fifteen feet fall, provided for each turn of the tide--both in the ebb and the flow, so that there should be a continuous motion to the machinery. Near the mouth of the shaft two large boiler-iron reservoirs were constructed, capable of holding from one hundred and fifty thousand to two hundred thousand cubic feet of compressed air, the average rate of condensation being about two hundred atmospheres. These reservoirs were properly connected with the pumping apparatus of the bridge by large cast-iron mains, so that the supply was continuous, and at an almost nominal cost. It was by the same power of compressed air that the tunneling through Mount St. Gothard was effected for the Lyons and Turin Railway, just completed. The first operations were to enlarge the shaft so as to form an opening forty by one hundred feet, English measure. This consumed the greater part of the year 1849, so that the real work of sinking was not fairly under way until early in 1850. But from that period down to the memorable 5th of November, 1872, the excavation steadily progressed. I neglected to state at the outset that M. Jean Dusoloy, the state engineer of Belgium, was appointed General Superintendent, and continued to fill that important office until he lost his life, on the morning of the 6th of November, the melancholly details of which are hereinafter fully narrated.