May 15, 1879] 



NATURE 



61 



Congress, the numbers corresponding with those on the 

 sketch-map which we give. The first six lie within the 

 United States of Columbia, and the last in Nicaragua 

 and Central America. 



1. This line is in the state of Cauca, and extends from 

 the head of the Gulf of Uraba on the Atlantic side to the 

 bay of Chiri-Chiri. The total length between the two 

 oceans is 290 kilometres, of which 50 are canal proper, 

 and the rivers utilised would be the Atrato, Napipi, and 

 Doguado. The volume of excavation would amount to 

 29,000,000 cubic metres, and of embankment 3,000,000. 

 This canal would require twenty- two locks, and a tunnel 

 six kilometres long. There are a good many objections 

 to a canal along this line, which the American Commis- 

 sion placed only in the second class ; besides the locks 

 and tunnel, it would be difficult to make a good port at 

 Chiri-Chiri. It would take nine years to make. 



2. The second line is in the States of Cauca and 

 Panama, and runs from the head of the Gulf of Uraba 

 to Darien Harbour and the Gulf of San Miguel. 

 It is 235 kilometres long, 128 being canal, the rivers 

 utilised being the Atrato, Caquirri, Puquia, and Cud, 

 or rather the Tibule, Paya, and Tuyra. It would re- 

 quire 22 locks and I kilometre of tunnel, or without a 

 tunnel, extremely deep excavation. The material ex- 

 cavated would amount to 60,000,000 or 65,000,000 cubic 

 metres, and the embankments, &c., to 6,000,000. The 

 tertiary formation along this route presents comparatively 

 soft rocks, and there are fine ports at the two extremities. 

 It would take twelve years to make. 



3. The third scheme is in the same State as the pre- 

 vious, but the line goes from Acanti at the entrance to 

 the Gulf of Uraba, to the same Pacific terminus as 

 No. 2, utilising the Tolo, Tiati, Tupisa, Chucunaqua, and 

 the Tuyra. Its length would be 125 miles, of which only 

 74 would be canal. It would require 70,000,000 cubic 

 metres of excavation ; there would be no locks, but a 

 tunnelling of 17 kilometres, which is a great objection, 

 combined with the elevation of the point of departure 

 and the difficulty of sinking shafts. It would take twelve 

 years to make. 



4. This route lies in the Chepo district of Panama 

 State, going from the Bay of San Bias to opposite Chepillo 

 Island, at the head of Panama Gulf. The length is fifty- 

 three kilometres, forty-two being canal, the rivers utihsed 

 being the N ercalegua, Mamoni, and Bayano. The mate- 

 rial excavated would amount to only 34,000,000 cubic 

 metres, there would be no lock, but 16 kilometres of 

 tunnel. This last point is, of course, an objection. The 

 length of time would be ten years. 



Nos. 5 and 6 are both in the Colon and Panama 

 departments of Panama State, and, as will be seen, are to 

 a considerable extent coincident. The former is 72 

 kilometres long, all canal, the River Chagres being made 

 use of. The amount of excavation would be 57,000,000 

 cubic metres, and of embankment 5,000,000; there would 

 be 25 sluices and no tunnel, and it would take six years to 

 make. No. 6, again, would have no sluices, but tunnelling 

 6 kilometres long, with 47,000,000 cubic metres of excava- 

 tion. It would be 75 kilometres long, and the rivers 

 Chagres and Rio Grande would be utilised. Each would 

 take about six years to make, and would cost about the 

 same sum. They are near the Panama Railway, pass 

 through a well-peopled region, and there is no difficulty 

 as to ports. Lieut. Wyse's commission, however, advo- 

 cate warmly No.^6 scheme, as being preferable to any 

 other. The time wasted in passing locks, the difficulty 

 and expense of maintaining them, and other considera- 

 tions, induce them to advise that all idea of a canal with 

 locks should be abandoned; and of all possible level 

 canals with tunnels, that numbered 6 seenis to this 

 commission altogether the one presenting the mest 

 favourable conditions. 

 The scheme numbered 7 is in the state of Nicaragua 



and Costa Rica, and passes from Greytown on the 

 Atlantic side, to the Bay of Brito on the Pacific. This 

 line would be 292 kilometres long, 195 being canal, the 

 San Juan, Lake Nicaragua, and the Rio Grande being 

 utilised along the route. The excavations would amount 

 to 48,cxx),ooo cubic metres, and embankments, &c., to 

 5,500,000, and there would be twenty-one locks and no 

 tunnel. There are too many objections to this line to 

 attract the favourable consideration of the Congress. 

 There are, e.g:, the complete absence of ports, difficulty 

 of constructing and maintaining them, insalubrity of 

 nearly the whole of the Atlantic slope, length of the 

 canal, and the political instability of the countries con- 

 cerned. It would take ten years to make. 



As to the cost of the various schemes, we may say that 

 it varies from 475,000,000 to 650,000,000 francs, with 

 a yearly sum for maintenance of from 4,000,000 to 

 15,000,000. 



Some statistics as to the dimensions proposed to be 

 adopted for the basin of the canal may be of interest. 

 The breadth of the canal will be about 20 metres at the 

 bottom, 26 metres at 3 metres high, and according to the 

 nature of the ground, from 32 metres as a minimum 

 at the surface in deep cuttings to 50 metres, when 

 steep banks require 2 in i of fall. The increase in breadth 

 which is proposed at 3 metres above the bottom is intended 

 to give more play to ships of large bulk and to increase 

 the water-section, which would thus never be less than 

 224 square metres. The depth of the canal would be 8^ 

 metres. The curves proposed, with a minimum radius of 

 3,000 metres, are less pronounced than those in the Suez 

 Canal. The crossing stations will have a breadth of 40 

 metres at the bottom on a length of 500 metres. The 

 tunnelling will also have a depth of water of 8J metres, a 

 breadth of 20 metres at bottom, but only 24 at the sur- 

 face. The smallest water-section will thus be 187 square 

 metres. Above the mean level, on each side, there will 

 be a straight space of 4 metres, then an arch of 

 30° in a radius of 63 metres ; the summit will be 

 semicircular, with a radius of only 2 metres. To 

 satisfy all contingencies the height of the vault above 

 the level of the water will reach 34 metres, which will 

 allow the largest vessels to pass by a little adjustment of 

 their most prominent masts and yards. The entire 

 subterranean section will be 780 square metres, of which 

 563 will be above water. It is expected that throughout, 

 very little embanking will be necessary. 



Thus, so far as the International Commission is 

 concerned, the information to be laid before the confer- 

 ence is full and exact. So far as we have studied the 

 question there seems no serious physical or engineering 

 difficulty in cutting a canal through the American isthmus 

 between the Atlantic and Pacific ; probably the great 

 difficulty will be a monetary one, and even this need not, 

 we suppose, be insuperable, if all other difficulties are 

 removed. 



ON THE EVOLUTION OF THE VERTEBRATA^ 

 II. 



AMPHIBIA {continued).— V^htn the history of the 

 -^ development of these forms has been thoroughly 

 made out, the terminology can be put into something like 

 proper form. This will have to be done cautiously, for 

 that which we see as one bone in the larva represents, 

 and may become, two or three bones in the adult, and 

 these may represent bones that start as distinct centres 

 in the higher forms. 



In the Urodeles t\\i:re.\s on&hon&{t\it ptetygo-palaline) 

 in the larva which plays many parts during metamor- 

 phosis, and a different part in different species. At first 

 it is related to no cartilage at all, only arising as a cement 

 to a patch of palatine teeth, but after a time the ethmo- 



■ Abstract of Prof. Parker's Hunterian Lectures, delivered at the College 

 of Surgeons, commencing on February lo. Continued from p. 32. 



