May 12, 1856.] KELLEY. 71 



to the river Napipi presents successive elevations ; and it would be 

 an additional service to geography, if you would cause this route to be 

 levelled. 



The Peesident then rose and observed that, as a previous evening had been 

 given to the general question, and the strictly engineering question as to 

 cuttings had been discussed already, and as there seemed to be no engineering 

 difficulties that could not be overcome, he proposed to confine the discussion 

 of this evening to the remaining portion of the subject, that of the water-level, 

 or Avhat might be properly called the hydraulic part of the inquiry ; for if this 

 should be found to be impracticable, the engineering portion would necessarily 

 fail also ; and as there might be some gentlemen present who had not heard 

 the reading of the paper, he would mention a few of the leading points as they 

 had been stated for their guidance. The proposition before the Society was 

 to unite the Atlantic with the Pacific Ocean by means of a channel without 

 any lock, by which ships of great burthen could freely pass from one 

 ocean to the other ; and it was proposed to effect this by means of the 

 Atrato, using the lower part of that river as far as the junction of the Truando, 

 a tributary river, and thence either to make use of the bed of the Truando as far 

 as possible, or turn its stream into the Pacific by means of a canal. It had been 

 ascertained that the mean water-level of the two oceans was the same, and it 

 was assumed from the observations which had been made, that the point of the 

 junction of the Atrato with the Truando was 15 feet above that level, and that 

 the distance of this point on the one side was about 61 5 miles, and on the 

 other about 63 miles. With these facts the question of interest was, whether 

 under the proposed circumstances the water could be maintained in these two 

 arms at such a level, considering the supply and the drainage, as would render 

 the communication available at all times ; and what would be the efiect of the 

 tide of the Pacific in passing up such a channel, whether it would facilitate or 

 render more diflicult the object in view ? These were questions of the highest 

 moment and of greatest interest ; and seeing that the Meeting was favoured 

 with the presence of several of the most eminent engineers of this country, he 

 would leave the question in their hands, and ask Mr. Robert Stephenson to 

 favour the Meeting with his opinions first : the point being not so much to 

 consider the details of the question, as to determine whether the facts were 

 sufiiciently promising for the recommendation of a more accurate survey being 

 undertaken. 



Mr. Robert Stephenson, f.r.g.s., said that the President seemed to fear a 

 difficulty in reference to the tidal action at the junction of the Truando and 

 Atrato. Considering the oscillation of the Pacific to equal that in the Severn, 

 still it would present no difficulty to him. The distance is about 130 miles 

 from sea to sea : no river in England was exposed for nearly so great a dis- 

 tance to tidal action ; even the case of the Severn was exceptional. The 

 engineering difdculties did not seem to him to be serious ; but, as he was 

 excluded from that side of the question by the decision of the Pi-esident, he 

 would simply add, that the great difficulty appeared to him to be in making 

 a good entrance into the Atrato. At the entrance of that river vast quantities 

 of mud had been deposited, and a delta of great extent formed, enclosing a 

 series of lagoons, through which no permanent channel is maintained ; and this 

 is the case of all rivers that fall into a tideless sea. The success of the scheme 

 would therefore depend on forming a good entrance to the river ; for this, 

 artificial communication would be necessary. He had no means of judging its 

 feasibility, but would assume that it was feasible on Mr. Lane's statement. 

 He concfuded by expressing his high sense of the enterprise and liberality of 

 Mr. Kelley. 



In answer to a question from the President, Mr. Stephenson explained 



I 



