I have studied diligently the subject of earthquakes, and their effect upon the isthmus, having consulted the following authorities: Baron A. Von Humboldt, Pilla, A. Erman, Perrey, Sarti, Soldani, Dr Yung, and Dr A. Rojas.
The cataclysms and earthquakes recorded in South and Central America have never proved destructive on the isthmus to an extent that would injure seriously a canal.
From observations by Perrey during many years, the following is the yearly average of earthquakes throughout the earth: 23 in winter, 15 in spring, 20 in summer, 22 in autumn; 80 the whole year.
We visited the isthmus during the two seasons of maximum recurrence, and only experienced three earthquakes, one strong, but which would have been harmless to the canal, and the other two quite insignificant.
Quito, Venezuela, and Chili are the points of the continent whence earthquake-waves are mostly propagated toward the isthmus.
The earthquakes of 1852 are the most striking general earthquakes recorded, and in Oajaca and Vera Cruz only a few houses were cracked. At all events, they were not calamitous. These earthquakes began on the 17th of January, by an eruption of the Mauna Loa, nearly destroying the Sandwich Islands. In July, Cuba and Porto Rico suffered terrible losses in life and property; on the 17th of the same month it was felt in Ceuta; on the 18th in Santo Domingo; and in Austria it was so violent that the shock rung the church-bells; on the 25th it was felt in Georgia, United States; on the 16th of September the inhabitants of Manila experienced the heaviest oscillations in their records; St Iago of Cuba was completely destroyed, and at almost the same instant the Etna entered into one of its most terrible eruptions. It will be seen that there must be some reason holding good for the safety of the isthmus, when it escaped the commotion of a centre of disturbance comparatively close, while distant points were violently shaken.
The general earthquake of 1867, which proved so calamitous in the West Indies, was harmless in the isthmus.
The above is not presented as a proof, but only as a plausible deduction, tending to show the stability of the isthmus.
There are strong reasons to confirm the belief that Calabria, Tuscany, Portugal, Cuba, and Japan are subject to heavier commotions than any isthmian route will ever be; and yet this danger is never taken into account in connection with public works, or commercial and political enterprises.
The data obtained from our surveys are not sufficient to make estimates as to the cost of the canal.
I have thought it advisable to exaggerate the dimensions of all the elements tending to exhaust the summit water supply, and to tunnel for the feeder in localities in which I had reason to believe that an open cut would be less expensive.
I believe that the cost of the feeder is not incommensurable with the importance of the canal.
For the purpose of comparison, we have the Croton aqueduct, which brings water to New York from a distance of 41 miles. In its construction, it has been necessary to prepare an immense drainage area, to make costly improvements, and an expensive dam at the Croton River; to bring the water through
