COLOMBIA, UNITED STATES OF. 



I arrived ut Oarthagena on December 19, 

 t<>.>k in supplies and carried oft' a con- 

 ,Mo nuiiilier ut' laborers, with whom she 



r IUT destination on tho 27th of the same 

 month. The time from February to July had 



spent by tho first exploring expedition 



:t! inn, thorough, scientific examination 

 of tin- isthmus; every probable, rumored, or 

 suspected pass, from Aspinwall to San Bias 



\\as diligently and carefully explored 



lit success, as the Cordilleras proved a 

 1'ormiduMo barrier at every point. 



Tho southern part of the isthmus is still un- 



rod, and it is the impression, among scieu- 

 tilie engineers most familiaiuvith tho country, 

 that the Atrato route, from the Gulf of Darien 

 u 1 1 tho Atrato to the "divide," thence down 

 the Tuyra to the Gulf of San Miguel, on the 

 Pacific side, offers the most encouragement for 

 the construction of an eligible ship-canal route. 

 The main advantages of this route consist in the 

 fact that the channels of both the Atrato and 

 Tuyra Rivers are very wide, and have a suffi- 

 cient depth of water at all seasons of the year 

 for vessels of the largest class for a considera- 

 ble distance upward. The harbors on the 

 Pacific, as well as on the Atlantic coast, are 

 said to be excellent, and to need but little 

 improvement to make them at all times ac- 

 cessible. 



The President of the United States ordered 

 Commander Selfridge to start at once for the 

 survey of this route, and to leave no stone un- 

 turned before giving up the researches in that 

 part of the isthmus. While capitalists and 

 projectors have hitherto taken it for granted 

 that tho canal must be horizontal with the 

 tu-(> oceans, as no reservoir to provide the 

 locks can be found on the crest of the moun- 

 tain, it appears that President Grant has also 

 taken into consideration a project of a different 

 nature, suggested to him by eminent and ex- 

 perienced engineers and surveyors. The plan, 

 which was at the bottom of all previous ex- 

 ploring expeditions, consisted in either cutting 

 or tunnelling the Cordilleras at the place best 

 suited for such a purpose. But, as it is sup- 

 posed that no place can be found where the 

 crest of the mountain is less than several hun- 

 dred feet above the level of the ocean, the 

 catting of a ridge deep enough to answer the 

 purpose in view would necessitate such an 

 enormous outlay of capital that the execution 

 of the work would be altogether beyond the 

 means of any private company, and would even 

 tax tho wealthiest nation too severely. On 

 the other hand, the tunnelling through such a 

 broad ridge of solid rock would, to all ap- 

 pearances, be even more expensive. 



The new plan, which is said to have been 

 duly weighed and considered, is to search for 

 the most feasible surface-route, and construct 

 a canal over instead of under the Cordilleras. 

 Mr. J. Medill, an engineer of high repute, in a 

 recent communication to a contemporary, says: 



" To construct a ship-caaal on the natural 



COLVEB, NATHANIEL. Ill 



surface over the isthmus, and to i-<jiii|> it with 

 double locks, would require n<> deep cutting 

 ami no tunnelling, and will be conceded by 

 engineers to be entirely practicable; nor would 

 the cost exceed tho means of a company of 

 capitalists which can easily be organized to 

 execute it. All that remains would be to sup- 

 ply it with sufficient water, and the cost of 

 so doing is readily computable, and will amaze 

 many persons by reason of its comparative 

 smallnoss. I take it for granted that a route 

 may be found where tho elevation would not 

 exceed 500 or GOO feet. The Aspinwall route 

 is only 800 feet, but the harbors are bad. Per- 

 haps, on the Atrato route, where excellent 

 harbors are found, the pass can be surmounted 

 at an elevation not exceeding 500 feet. But, 

 whatever the altitude may be on the line 

 selected for the canal, only a part of the water 

 for the locks and levels would need to be sup- 

 plied by artificial power. The rainy season 

 on the isthmus lasts two-thirds of the year. 

 Feeders from the numerous mountain-streams 

 would furnish a large part of the lockage-water. 

 Reservoirs could be established to increase the 

 supply, and only on the upper levels would the 

 canal have to depend entirely upon the pumps. 

 The rainfall into the canal would make good 

 for eight or nine months in the year all loss 

 by evaporation or percolation, leaving, for 

 steam-power, streams and reservoirs to furnish 

 lockage- water. All objections, that can be 

 urged against the feasibility of filling locks by 

 steam-power to float ships over elevations, will 

 also lie against attempting to move trains or 

 cars over mountains by the same power. In 

 both cases it is only a question of overcoming 

 the gravity of a given weight to bo elevated a 

 given height. The locomotive is obliged to 

 move itself up a grade as well as to drag its 

 load. A stationary engine can expend its 

 whole power to lift its load, and has not to 

 lift itself, nor a stock of fuel and water. On a 

 grade of 70 to 90 feet to the mile a locomotive 

 expends, perhaps, a quarter of its power to 

 move itself and tender, and in wet weather, 

 when the track is slippery, even more than 

 that proportion. The cost of coal used for a 

 locomotive or a stationary engine is compara- 

 tively small; a few hundred- weight of coal 

 burned under the boiler of a locomotive will 

 produce steam-power hi such force and quantity 

 as to elevate 400 tons of engine, trucks, and 

 freight, up a grade 400 feet high in an hour. 

 A stationary engine of tho same horse-power 

 would lift twice the weight the same height 

 in tho same time." 



COLVER, Rev. NATHANIEL, D. D., a Baptist 

 clergyman, orator, reformer, and promoter of 

 education, born in Orwell, Vt., in May, 1794 ; 

 died in Chicago, 111., September 5, 1870. His 

 early advantages of education were limited, 

 but were diligently improved. He was a vol- 

 unteer in the "War of 1812, and subsequently 

 engaged in business as a tanner. It was not 

 till he was married and settled in life that he 



