Page:Vol 6 History of Mexico by H H Bancroft.djvu/690

670 Number of Divisions. Limits of Divisions. Length of Divisions. Remarks.

— Calculations for the Water Supply, and Best Form of Cross-sections to be Given to the Artificial Watercourses. — The length of the canal proper will be about one hundred and forty-four miles from the harbor at Salina Cruz to the island of Tacamichapa on the Coatzacoalcos River. Fifty-two miles of this length will form the descending branch from Tarifa to the Pacific. With the exception of Tarifa Pass, there will be no necessity for using lock-flights, and even here, every reach may hold two full lock-lengths, and enough development can be found on the hillside to avoid the grouping of more than two locks at a flight.

The dimensions proposed for the canal are:

I should recommend double locks; but the estimates that follow suppose each lock subdivided by gates affording respectively 130, 218, and 320 feet of lockage length.

It is extremely difficult, nay, impossible, to determine the amount of water required to feed a canal, unless the condition and nature of its trade are known. This is especially the case when the transit has to be effected through an undeveloped country, under very anomalous political, social, industrial, and economical conditions. I do not feel justified in using the custom commercial statistics before me of the probable commerce that may seek this channel, because for my purpose I have no confidence in them, and no good reason to suppose that this manner of guessing is more rational than any other one, so long as any guessing element enters into the problem. I believe that, through this canal, an immense impetus will be given to the commerce of our Pacific States; that the politico-economical laws of our development demand its immediate construction; that the length of many trading channels will be shortened, and that the capital now eliminated through losses of money, time, and deterioration of merchandise, will be redeemed, and made useful in its application to cheapen produce and increase trade; but I also