Note XXXIV-51 — Chapter XXXIV · INTEROCEANIC COMMUNICATION. 1801-1887.

'It is ascertained,' says Captain Fitzroy, 'that there is only a trifling difference between the levels of the ocean at this Isthmus. A rise of tide not exceeding two feet is found on the Atlantic side, while in Panama Bay the tide rises more than eighteen feet; the mean level of the Pacific in this particular place being two or three feet above that of the Atlantic. It is high water at the same hour in each ocean.'

Colonel Lloyd says that the Pacific at high water is thirteen feet higher than the Atlantic, while the Atlantic is highest at low water by six feet. Baron Humboldt said, in 1809: 'The difference of level between the Caribbean Sea and the Pacific Ocean does not, probably, exceed nine feet; and at different hours in the day, sometimes one sea, sometimes the other, is the more elevated.' But this difference would be no hindrance, but, on the contrary, a most important advantage in a ship-canal, since it would create a current from the Atlantic to the Pacific during the ebb, and one from the Pacific to the Atlantic during the flood-tide of the Pacific, and these alternate currents would enable each of the fleets to pass through at different times, those bound from the Atlantic to the Pacific during the ebb-tide of the latter, and those from the Pacific to the Atlantic during the flood-tide of the former. This arrangement in the periods of transit would afford many advantages, such as obviating the meeting of the vessels, and the necessity of their passing one another, and preventing their accumulation or crowding together in the canal, as each fleet could be carried right through in one tide, if not by the current alone, at least with the aid of tug steamers. The alternation of the currents would have the further beneficial effect of washing out the bed of the canal, and keeping it free from the deposition of sand or mud, so that dredging would never become necessary; and would also render the degree of width necessary for the canal less; though I do not reckon this to be a point of moment, as the wider and deeper it is cut the better, and the work once finished will last to the end of the world, since the natural effect of the alternate currents will be a gradual process of deepening and widening, which will convert the canal into a strait.