We should see the industrial resources—which have drawn thither in the struggle for existence the most energetic of the races of the globe—giving occupation to a happy and united people. The hum of industry, and the din of the steam hammers, would mingle together with smoke of furnaces and of factories, above the inexhaustible coal fields of Pennsylvania, Virginia, Illinois, and Iowa. The grain of Kentucky, Ohio, Indiana, and Kansas would be shipped to New Orleans, to be exchanged for the cotton and sugar of the South, and the coffee, dyes, and tobacco of Costa Rico, Havana, and Ambelema; the magnificent table lands of Mexico, Guatemala, Yucatan, and the plateau of Bogotá, occupied by a people more highly cultivated and capable of appreciating the grandeur of the scenery and salubrity of the climate, and of utilizing the fertility of the soil and the physical advantages of those most favored regions. Opulent cities would spring up in the bays of Tampa, Mobile, and Pensacola. New Orleans, Galveston, and Vera Cruz would rival Marseilles and ancient Venice. From the ports of Carthagena, Sabanilla, Maracaibo, and Para, would be shipped the produce of the valleys of the Magdelina and the Amazon. Great as would be the transformations effected by these changes, they would be less than those which have transformed the continent of America into a congeries of civilized States. Such speculations have a sober basis of fact. They are not wholly useless if they attract the attention of those who have more time for patient investigation. Sufficient has been said to show that the objects to be attained merit consideration. CHAPTER V. Admiral Davis’s Report—Table of the Tunnels of the different Isthmean Routes—Altitude of Ridge at Darien—Comparative Cost of Canals with and without Tunnels—Lift Locks and Thorough Cut—Tide in the Atlantic and Pacific—Moderate Lockage can not Obstruct the Navigation—Gisborne on Thorough Cut—His Error as to Velocity of Water—Objections to Strait—Tabular Statement of the Cost of Tunnels, English, French, German, and American—Tunnel of Mont Cenis—Hoosac Tunnel—Profiles of Mont Cenis and Hoosac Tunnels—Dimensions of Ship Tunnel—Cost of Open Canal—General Michler’s Report—Guard Locks Necessary—Cost of System of Lift Locks—Conclusions Supported by Garella and Michel Chevalier. In compliance with a resolution of the Senate, dated March 19, 1866, we have an admirable report from Admiral Davis. In this report the relative merit of different lines is exhibited; carefully prepared tables, showing the amount of freight which would pass the Isthmus; a list of ninety publications and fourteen maps, are appended. Ten of these maps, based on recent surveys, supply much valuable information.