May 12, 1856.] KELLEY. 73 



thirty-one millions. The sum was great, but the object was still greater ; and 

 considering that the distance round the vast peninsula of South America was 

 estimated at nineteen thousand miles from New York to San Francisco, and 

 that by the canal it would be reduced to 5700 miles — considering also that 

 the passage round Cape Horn was seldom less than one hundred and fifty days^ 

 and often above two hundred and fifty days ; that the passage by the caiial 

 would be made in one hundred and five days ; that the cost of maintaining the 

 ship and crew of a fast vessel, including insurance and all charges, would be 

 10,475 dollars, not including the extreme contingencies of shipwrecks and loss 

 of human life, Mr. Rennie was of opinion that the vast advantages which 

 would accrue to the world at' large were well worth the sacrifice. 



Mr. Beaedmore, f.r.g.s., remarked that there were one or two facts and 

 first principles of science which might be laid down as axioms. 



The first was the relative level of the two oceans : he believed it to be a 

 consequence of the law of gravitation that the mean level of the ocean was 

 substantially the same at all parts of the globe, and would be so as long as a 

 pound of sea water everywhere occupied the same space, and was composed of 

 the same constituents. He had investigated every kind of available observa- 

 tion on the level of the ocean, including the Ordnance Survey of Great Bri- 

 tain, and the testing levels taken at the instance of the British Association 

 between the English and Bristol Channels, and connected with the admirable 

 surveys of the President (Admiral Beechey), and had in his own professional 

 experience made numerous minute surveys, all of which c6nfirmed this view^ 

 Where surveys showed difierent results, it was because the mean tide level had 

 not been ascertained with sufficient accuracy. 



He had also investigated the facts presented by Mr. Kelley, which appeared 

 to him to prove incontestably that the junction of the Atrato and Truando 

 could not vary materially from the stated height of fifteen feet above the 

 mean sea level. With these facts, combined with the rise of twelve feet tide 

 in the Pacific, the questions before the Meeting were — 



Firstly. Whether a free communication between the waters of the Pacific 

 and the Atrato, at the point in question, would be practicable for navigation ? 



Secondly. Whether such a communication would be likely to reduce the 

 level of the Atrato to a serious or injurious extent ? and 



Thirdly. Would it cause any tidal action of a prejudicial nature on that 

 river ? 



1. The first question might be answered in the affiimative without any hesi- 

 tation ; for the extreme fall could not possibly create a current greater than 

 from two to three miles per hour, where beyond the tidal action ; within it 

 there would be the usual flow and ebb, to be found in a somewhat sluggish 

 tidal river which has no great interior basin to fill or empty. 



2. The second question might be dealt with in a familiar way, by assuming, 

 for instance, that the Atrato had at present as much as four inches fall in any 

 or every mile of its course. Now the river was evidently one of very large 

 volume, and liable, from the character of the mountains draining into it, and 

 from the excessive rainfall of the climate, to heavy floods ; its width was 

 therefore great, and its depth varied from 45 to 85 feet. Assuming, then, 

 that it were possible to abstract sufficient water to reduce the surface fall to a 

 minimum of one inch per mile (a flatness rarely to be found), the depth at the 

 junction would only be reduced about ten feet, and the power of discharging 

 its waters would be reduced 50 per cent. ; or, in other words, one-half of its 

 entire volume would be available to fall through the new cut towards the 

 Pacific. But it must be remembered that, as the height of the Atrato at the 

 point of junction was reduced, so would the velocity down the new cut be 

 decreased, and therefore it would not in reality carry off any such proportion 

 of the volume. These statements are matters of well-known fact in the science 



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