For a tide-level canal, not only would the depth be 85 feet greater, but, as the slope could not be made steeper, the width of the whole cutting would be correspondingly increased. With reference to the slope of the sides, it is important to note that it has not been found practicable to adhere always to the proposed section, which has to be made flatter, thus considerably increasing the amount of excavation required. The behaviour of living rock is not susceptible of the precise specification which can be applied to quarried stone on the one hand or loose gravel on the other. Mechanically it is complex, both on account of its structure and of the _rôle_ which water plays in its economy. In the case of the Culebra rock, the volcanic dykes by which it is traversed have altered the nature of the rock in their vicinity, and the part played by water is considerable, owing to the wetness of the climate. Moreover, the rock does not remain wholly unchanged when exposed to air, but deteriorates by "weathering," a chemical and physical process which proceeds much faster in an equatorial climate than in the temperate zones. The climate, however, has a compensating action, in so far as the rapid growth of vegetation soon clothes and protects the scarped slopes, thus acting as a "revetment." * * * * * Alighting at Culebra station on the Panama Railway, and proceeding to the western side of the cut, one obtains the most impressive view of the Canal works, and this is the spot usually visited by travellers and tourists. I first stood there in January, 1907, and returned in April, 1908. The impressions obtained were very different on these two occasions. In January, 1907, after two and a half years of American occupation, what struck me most was the enormous mass of material which had been removed by the French companies, and the comparatively insignificant appearance of the American excavations, which could readily be distinguished from the older work, already coated with vegetation. It was then that I began to appreciate the heroic labours of the French engineers, whose achievements under circumstances of great difficulty are being daily more and more appreciated and praised by their successors. Turning to study the progress of work, I watched with delight the operations of the 100-ton steam shovels, which at a distance, when the human hands are not seen, appear endowed with volition, and remind the spectator of elephants at work. The cars were loaded with surprising celerity, and the dirt-train was hauled off to the distant dump by an old Belgian locomotive, part of the machinery taken over from the New Company. But then the hitch came--there were no cars to take the place of those already filled, and the steam shovel was idle. Looking round, I found that many other steam shovels and their crews were idle from the same cause, the machinery for transportation