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 AMERICAN SOCIETY 'OF CIVIL ENGINEERS. 
 
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 INTER-OQEANIC 
 
 Canal Projects. 
 
 By A. G. MENOCAL, Member Am. Soe. C. E. 
 
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 AMERICAN SOCIETY OF CIVIL ENGINEERS. 
 
 INSTITUTED 1852. 
 
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 transactions. 
 
 Note.—T his Society is not responsible, as a body, for the facts and opinions advanced in any 
 
 of its publications. 
 -► - 
 
 CLXXXVIII. 
 
 (Vol. VIII.—November, 1879). 
 
 INTER-OCEANIC CANAL PROJECTS, 
 
 > 
 
 By A. G. Menocal, C. E., Member of the Society. 
 
 Read November 19 , 1879 . 
 
 The object of the present paper is to present for discussion before 
 the Society of Civil Engineers a question which is now attracting much 
 public interest through the press of the country, and which deserves the 
 most attentive consideration by the engineer, on account of its magni¬ 
 tude, the engineering difficulties involved in the solution of the problem, 
 and the great interest the world at large has always shown, and will con¬ 
 tinue to show in the execution of the work. 
 
 It is evident that the American Isthmus has been sufficiently explored 
 by the U. S. Surveying expeditions, and by private parties interested in 
 opening a water passage, between the Atlantic and Pacific Oceans, to 
 enable us to determine the difficulties that would have to be met in the 
 construction of a ship canal at the several places pointed out as present¬ 
 ing favorable indications for execution, and on a careful examination of 
 all the available data, the question seems to have narrowed down to 
 Panama and Nicaragua as the only places where the work can be success¬ 
 fully carried out. It is to the discussion of the most prominent features 
 of these two routes, and their relative advantages and disadvantages that 
 I will confine myself. 
 
 Three projects for a canal at Panama have been seriously suggested 
 and estimated upon, two at the level of the ocean, and one with locks. 
 Of the first two, the one extending from the Bay of Colon to the Bay of 
 
 
312 
 
 Panama lias been devised by Lients. Wyse and Reclues of the French 
 Navy, and lately advocated by M. de Lesseps, the successful promoter of 
 the Suez Canal; and the other connecting the Bay of San Bias, on the 
 Atlantic, with the Rio Bayano in the Bay of Panama, was first partially 
 surveyed by Messrs. MacDougal and Sweet, in the interest of Mr. Kelly, 
 and subsequently re-examined by Commander Selfridge, U. S. N., in 
 1871, and Lieut. Wyse, in 1878. 
 
 The project for a canal, with locks, via Panama, was carefully 
 studied, and the line actually located by the U. S. Surveying Expeditiou, 
 under Commander E. P. Lull, U. S. N., in 1875, of which the writer 
 was the chief engineer. 
 
 Lieut. Wyse’s Plan. 
 
 This project was first presented for discussion before the International 
 Canal Congress, assembled at Paris, on the 15th of May of the present 
 year, and is fully described by the author in his report to the president 
 of the “ Societe du Canal Interoceanique,” dated April 4, 1879. As 
 originally projected it consisted of a thorough cut at the level of the 
 oceans, 73 200 metres (45.5 miles) in length, 20 metres (65.6 feet) wide, 
 and 8.5 metres (27.88 feet) depth of water, with a tunnel 72.20 metres 
 (4.8 miles) long. The river Chagres, as well as the Rio Grande, and 
 their tributaries to the number of 22, are to be received into the canal; 
 the only provision made to ameliorate the effect of such an enormous 
 volume of water is 191 000 cubic metres of excavation, in the beds of the 
 streams at the several points of junction with the canal. The estimated 
 cost of the work, as given by Lieut. Wyse, in his report, is 475 000 000 
 francs, or $95 000 000. This line is not one of actual location, but was 
 traced on a map of the isthmus, between Colon and Panama, constructed 
 from such information as could be obtained from the maps of the rail¬ 
 road and the survey of Mr. Garella, made in 1843 for a canal, with 
 locks, on a location other than that adopted by Lieut. Wyse. The eleva¬ 
 tions of the ground given in the profile were also obtained, as near as 
 practicable, from the same source of information, and the figures are, 
 therefore, to say the least, a rough representation of the natural 
 conditions. 
 
 This project was considered impracticable by the Technical Commis¬ 
 sion of the Paris Congress The sudden and high floods to which the 
 turbulent river Chagres, and its tributaries, are subject in the rainy 
 season, and the disadvantages under which those streams would have to 
 be taken into the canal, on account of the elevation of their beds above 
 
313 
 
 the sea, tlie proposed level of the canal, together with the current that 
 would he produced in the canal by the rise and fall of the tide in the 
 Bay of Panama (the spring tides amounting to 22 feet, would form such 
 impediments to navigation, and so many serious difficulties, and doubt¬ 
 ful elements in the execution and permanency of the work, that the plan 
 had either to be modified, or abandoned altogether. 
 
 A sub-committee composed of the following distinguished engineers, 
 wiz., Messrs. Buelle, Cotard, Couvreux, Favre, de Garay, Laroche, 
 Lavalley and Lepinay were appointed to estimate on the probable cost 
 •of the tunnel designed by Lieut. Wyse. They reported that, suppos¬ 
 ing the work free from water, its probable cost would be about 38 500 
 francs per lineal metre, or $59 444 000 for the length of tunnel proposed, 
 •and with 25 per cent, added for contingencies, $74 305 000. But if the 
 work had to be done under water, as it was thought would be the case 
 in that portion of the excavation below the level of the sea, then the 
 above estimate would be insufficient, and although the committee could 
 not, in that event, arrive at the approximate cost, it was of the opinion 
 that the expense would be increased by at least 100 000 000 francs or 
 $20 000 000. 
 
 To meet these objections Lieuts. Wyse and Reclues submitted several 
 plans, more or less feasible, from which the following modifications to 
 the original plan were accepted and estimated upon. A tide lock at the 
 Pacific terminus to keep the surface of the water in the canal at the mean 
 level of the Atlantic ; an open cut in place of the tunnel; and new chan¬ 
 nels to carry to the ocean the waters of the river Chagres, and its tribu¬ 
 taries, from Matacliin to the sea, independent of the canal, which should 
 be kept entirely free from all surface drainage. 
 
 These modifications were considered as an improvement on the first 
 plan; but the engineers differed widely as to the methods of execution 
 .and the practicability of the works proposed, at least, in a commercial 
 sense. 
 
 The above-named engineers, on consultation with the sub-committee 
 on locks and profiles, adopted uniform cross-sections and prices per unit 
 of work for all the projects submitted to the congress, and the modified 
 project was estimated according to the amount of work computed by 
 Lieut, Wyse at $208 800 000, exclusive of the indemnification to the 
 Panama Railroad. 
 
 The committee remarked in their report that such a sum had been 
 obtained by applying the adopted prices for labor and material to the 
 
314 
 
 quantities of work furnished them, increased by the sum of $8,400,000 
 named by the Committee on locks, as required, in its estimation for the- 
 canalization of the Chagres and its tributaries and necessary accessories, 
 and added that the committee was of the opinion “that the execution of 
 such works as the long, open cut proposed with a maximum depth of 
 321 feet above the surface of the water, and the construction of a new 
 channel for the Chagres, the stability of which would not be assured, 
 are subject to so many contingencies and difficulties that it was not pos¬ 
 sible to arrive at an estimate of their probable cost.” The competency of 
 the engineers hereinbefore named as composing that committee cannot 
 be doubted; they are men of high established reputation for integrity 
 and professional experience, and their figures and opinions are entitled 
 to full consideration. 
 
 I have made careful computations with the object of ascertaining the- 
 amount of excavation required for the open cut proposed, and in order 
 to arrive at as close an approximation of the cubical contents as the data 
 at hand would jjermit, the profile of the route submitted to the Paris- 
 Congress by Lieut. Wyse, has been altered by the substitution of the 
 line of actual location of the United States Surveying Expedition, from 
 the Chagres river to the Rio Grande, in lieu of the defective profile of 
 Lieut. Wyse. 
 
 It should be stated, however, that the length of the line has not 
 been changed, and that by the profile adopted I have been able to base 
 the computations on an elevation of the ground taken at every hundred 
 feet between those points, and that the dividing ridge is crossed at an 
 elevation of 294.7 feet above mean level of the sea, instead of 321.4 feet 
 as given in Lieut. Wyse’s profile. From Colon to the River Chagres, at 
 Matachin, and from the Rio Grande to Panama, no alterations have been 
 made, and the depths of the excavation have been taken from that pro¬ 
 file. For the sake of comparison the computations have been made 
 both according to the cross-sections proposed for the Nicaragua and 
 Panama canals, with locks, and that recommended by the Committee on 
 Locks at the Paris Congress. 
 
 The following are the results obtained, viz.: 
 
 1st. With the cross-sections adopted for the Nicaragua canal: 
 
 Excavation in rock above the level of the sea. 61 329 477 
 
 Excavation in rock below the level of the sea. 14 111 806 
 
 Total rock cub. yds, 
 
 75 441 283 
 
315 
 
 Excavation in eartli above the level of the sea. 15 904 339 
 
 Excavation in earth below the level of the sea. 7 046 970 
 
 Total earth cub. yds. 22 951 309 
 
 Grand total of excavation in earth and rock, cubic yards. 98 392 592 
 
 Besides this amount, there will be required no less than 1 800 000 
 'cubic yards of rock excavation under water in the bays of Colon and 
 Panama. 
 
 2nd. With the cross-section recommended by the Paris Congress: 
 
 Excavation in rock above the level of the sea. 38 821 559 
 
 Excavation in rock below the level of the sea. 11 741 022 
 
 Total rock, cub. yds. 50 562 581 
 
 « 
 
 Excavation in earth above the level of the sea.... 14 694 916 
 
 Excavation in earth below the level of the sea. 8 667 733 
 
 Total earth excavation cub. yds. 23 362 649 
 
 Grand total of excavation in rock and earth. 73 925 230 
 
 Or cub. metres. 56 183 174 
 
 Which is 10 000 000 cubic metres in excess of the total amount of 
 'Excavation estimated by Lieut. Wyse for the Paris Congress, on the 
 same cross-section. The amount of rock and earth have been computed 
 .according to the geological profile submitted by Lieut. Wyse. It will 
 be observed that the total cube of excavation required with the cross- 
 section proposed by the Paris Congress, is about 25 per cent less than 
 the amount obtained by adopting the cross-section proposed for the 
 canal by Nicaragua. This is due to the insufficiency of the slopes for 
 rock allowed by the Congress, viz : a vertical cut below and two metres 
 above the water line, and an inclination of one-tenth above that point to 
 the top of the rock. On the Nicaragua route one-half horizontal to one 
 vertical, from the bottom of the canal to ten feet above the water, and 
 one-fourtli horizontal to one vertical above that point to the top of the 
 rock, were considered necessary to obtain the permanency of the w T orks, 
 and they were so adopted throughout the line. The water prism for the 
 canal in rock proposed for the Nicaragua line is 2 418 square feet; that 
 recommended by the Congress is 2 012 square feet. Nevertheless, it 
 lias been repeatedly stated by the friends of the Panama scheme that the 
 
316 
 
 dimensions proposed for the Nicaragua route are insufficient for a ship 
 canal, and that to this fact is due the large difference in the estimated 
 cost of the two routes. It is well known to those informed of the vari¬ 
 able geological formation of the isthmus, as observed in the digging of 
 wells, excavations for railroads, gold and siver mines, and other works, 
 that vertical cuts and slopes with an inclination of one horizontal to ten 
 vertical are impracticable for the proposed work with a total length of 
 continuous deep cut of 41^ miles, with an extreme depth of 322.5 feet 
 above the bottom of the canal, and a mean depth of 174 feet for a dis¬ 
 tance of ten miles. 
 
 The amount of excavation herein given is exclusive of what may be 
 found necessary to provide a new channel for the river Chagres and its 
 tributaries from Matachin to the sea, a distance of 28 miles, as recom¬ 
 mended by the Congress. No data has been obtained to enable us to 
 arrive at an approximate cost of that work, estimated by the Congress at 
 $3 400 000. The engineer may, however, appreciate the magnitude of 
 that undertaking from the fact that the river Chagres, at Matachin, the- 
 point of its confluence with the canal, rises about 36 feet in times of 
 flood; that the bed of the river is about 40 feet above the level of the sea, 
 and has an inclination of 4| feet per mile for a distance of 12 miles- 
 above that point. That the channel attains a width, in times of flood, of 
 1 500 or more feet, a sectional area of 15 000 square feet, a current of 7.' 
 miles an hour, and a discharge of about 160 000 cubic feet per second. 
 The inclination of the bed decreases considerably below Matachin, and 
 as its volume is materially swelled by the addition of affluents with large- 
 flow, the sectional area of the new channel will have to be increased in 
 proportion. Below Matachin the river, for a distance of 10 miles, runs- 
 in a narrow valley confined by high precipitous hills, approaching from 
 both sides. This valley is to be occupied by the canal, the width of 
 which, at the top of excavation, will be about 500 feet. The new chan¬ 
 nel for the river will, therefore, have to be cut through the high hills- 
 on the north, and protected across the narrow valleys by heavy embank¬ 
 ments, and, in some cases, masonry walls. Similar difficulties, but on a 
 smaller scale, will have to be met on the south side of the canal in canal¬ 
 izing the river Trinidad and other large streams, tributaries to the 
 Chagres from that side. 
 
 The difficulties and contingencies involved in the execution of such 
 works, considering the location, climate, rainfall, etc., cannot be approx- 
 
imately estimated with our present information. Their stability, if ever 
 completed, could not be assured, as they will be constantly menaced with 
 total destruction by the periodical floods of the rivers. 
 
 Canals wtth Locks from Colon to Panama. 
 
 In 1875 the Government of the United States, at the request of the 
 Commission appointed by the President to examine the different sur¬ 
 veys made for an Inter-Oceanic Canal, and to report as to the line pos¬ 
 sessing the greatest advantages, sent out an expedition to ascertain the 
 practicability of a canal, with or without locks, across the Isthmus of 
 Panama. In a preliminary examination of the route, it was observed 
 that the high water marks of the river Chagres, in the vicinity of Mata- 
 chin, disclosed the fact that the river was subject to freshets, which 
 raised its surface to no less than 36 feet above its level in the dry season, 
 which latter was 42 feet above the sea. All idea of a canal without locks, 
 or of utilizing the bed of the river for ship navigation, was therefore 
 abandoned, and attention was directed to the location of a canal with 
 locks that would cross the river at such an elevation as would give a free 
 flow underneath to the highest floods. The summit level of the canal 
 was, on that account, fixed at an elevation of 123f feet above the mean 
 
 level of the sea, as follows: 
 
 Elevation of highest water mark. 77.70 
 
 Rise of arch. 14.05 
 
 Thickness of arch..'. 6.00 
 
 Depth of water in the canal. 26.00 
 
 Elevation of summit level, feet. 123.75 
 
 The river is proposed to be crossed by means of an aqueduct having 
 12 spans of 90 feet each, 1 900 feet extreme length, 65 feet wide and 26 
 feet deep. 
 
 The water to supply the canal will have to be obtained from the 
 upper Chagres by means of a feeder 10i miles long, and involving seven 
 tunnels with an aggregate length of 13 700 feet, and two siphons of 4 530 
 feet and 12 000 feet in length, respectively. 
 
 Careful gauges of the river Chagres, on the 15th of March, 1875, 
 showed the discharge, at the point the feeder leaves the river, to be 
 55 900 800 cubic feet per day : an amount of water sufficiently large to 
 supply the canal with 80 lockfulls per day, and to amply provide for 
 evaporation, leakage and filtration. In the month of April of the follow- 
 
318 
 
 ing year, in passing across the Isthmus, I had occasion to observe that the 
 river was lower, by at least one-tliird than at the time when the gauges 
 were taken the previous year. Should my estimate be correct, it would 
 evidently show that the supply, to say the least, could not be relied on 
 at all times. 
 
 The line was carefully located from the Atlantic to the Pacific, de- 
 veloiDing an extreme length of 41i miles. The dividing ridge was crossed 
 at an elevation of 294'. 7 above mean half tide, giving an extreme depth 
 of excavation of 171', plus the depth of water in the canal. 
 
 One tide lock is proposed in the Bay of Panama, and 24 lift locks, 12 
 on each side, of 10.3 feet lift each. The latter were located at those 
 points offering the greatest facilities for construction, with a saving in 
 the excavations. The form and dimensions of the cross sections for ex¬ 
 cavation in earth and rock, as well as the prices adopted, were for pur¬ 
 poses of comparison exactly the same as had been recommended for the 
 Nicaragua route. The estimated cost, including the necessary improve¬ 
 ments in the bays of Colon and Panama, was found, on carefully made 
 computations to be 894 511 360. Of this amount, 818 331 343 are esti¬ 
 mated for the construction of 16 culverts and the necessarv side drains 
 
 «/ 
 
 to dispose of the surface drainage independent of the canal. The dis¬ 
 advantages of this route are : the length of tunneling and siphon re¬ 
 quired for the feeder, a doubtful supply of water, an aqueduct 1 900 feet 
 long, swamp lands to be traversed by the canal, large mean annual rain 
 fall of 124 inches, and total lack of building material of all kinds fit for 
 the construction of the works recommended. The advantages are : short 
 route from sea to sea, and fair harbors on either side. The railroad, in 
 close proximity to the projected line, is a favorable condition, provided 
 that its owners are willing to give up their franchise for all purposes at 
 the cost of construction or a reasonable consideration, upon which I will 
 not venture an opinion. 
 
 * The San Blas Boute. 
 
 This is well known to be the shortest route between the Atlantic and 
 Pacific Oceans ; a favorable feature which, with an excellent harbor on 
 the Atlantic side, has always attracted the attention of those interested 
 in the solution of the problem of interoceanic canal communication, 
 The line has not been surveyed throughout its length, but from the par¬ 
 tial examinations made by Mr. MacDougal, in the interest of Mr. Kelly 
 of New York, in 1864, and by Commander Selfridge in 1871, its total 
 
319 
 
 length has been approximately placed at 30 miles, of which from seven 
 to ten miles will require tunneling. 
 
 Based on information obtained from these surveys, plans have been 
 prepared for a canal at the level of the sea, the cost of which was esti¬ 
 mated by the Paris Congress at $261 536 595, the tunnel having a section 
 of 1 315 square yards and a length of 8.7 miles. 
 
 The main objection to this route is the long tunnel required to pierce 
 the Cordilleras separating the two oceans, having an elevation of from 
 1 100 to 1 500 feet. 
 
 The available data is not sufficient to enable us to determine the pro¬ 
 bable cost of that work ; but it seems to be generally admitted, it will be 
 so large as to exclude it from the number of practicable schemes, at least 
 in a commercial sense. There is no doubt that great difficulties would 
 have to be met in the opening of a tunnel of the dimensions proposed for 
 ship navigation, and it seems to be equally true that almost all the plans 
 suggested to overcome them have been based on assumptions as to the 
 natural conditions. The limited knowledge we have at present of the 
 geological formation of the isthmus has been gained from examinations 
 of surface indications, deep wells, gold and silver mines, the excavations 
 for a few railroads, at far distant points, and the banks and beds of 
 streams. Some of the printed reports on the subject rest on mere 
 superficial observations of only some of those sources of informa¬ 
 tion. For example : a geologist accompanying one of the expeditions 
 follows the trail of the surveyors for a distance of 10 or 12 miles, from 
 the coast by the traverses, collects a few specimens of rocks and pebbles 
 from the beds of the streams, takes some notes on the variable character 
 of the soil and rocks cropping out here and there, and returns by the 
 same way to tell us the fact, “ that the Atlantic slope of the Cordillera in 
 the vicinity of San Bias is composed of the older crystalline rock, such 
 as granite, syenite and diorite, while that on the Pacific side belongs to 
 the later eruptive period, and its rocks belong to the families of the 
 trachyte and of the basalts, etc., etc.” Had he gone but a few miles to 
 the west he would undoubtedly have found at the head waters of the 
 Chagres, deep gulleys or canons cut in a continuous mass of soft lime 
 stone ; and not far from there, blocks of trap rock and other varieties of 
 stone, which might have somewhat modified his conclusions. Informa¬ 
 tion so superficial as the above does not seem to “ afford a sufficient 
 .guarantee that the rock to be met with in piercing a tunnel on the San 
 
320 
 
 Bias route will, for the most part, prove to be of a character sufficiently 
 homogeneous and firm to be self-sustaining,” as has been assumed in 
 computing the cost of a canal by that route. We have not the data to 
 affirm that the contrary will be the case ; but the indications are, I be¬ 
 lieve, pointing to that conclusion, and the chances are, to say the least, 
 just as much in favor of as against it. 
 
 The only way to arrive at the information required for the proper 
 understanding of the subject, and to obtain the data for a fair estimate of 
 cost, would be by sinking a number of shafts to the bottom of the canal 
 on the line of the proposed tunnel. In this manner the character of the 
 rock, and the quantity of water that would flow into the excavation when 
 made, can be approximately determined. Boring with the diamond drill 
 would show the character of the material to be met with, but would not 
 furnish satisfactory information as to filtration. Until that is done the- 
 question may be considered as resting on mere guessing , in which the 
 opinion of those who have been on the ground and gained information 
 by actual observations should be entitled to most consideration. It is 
 certain that in the construction of an isthmus ship canal at the level of 
 the sea, it will be necessary to contend with water from filtration. This 
 can be drained to the lower levels, while the bottom of the excavation is 
 sufficiently high above the sea to allow the flow by gravitation ; but 
 below that level the work will probably have to be done under water. 
 
 Pumping by different processes has been suggested as a means to- 
 overcome this difficulty, but the experience acquired from a close obser¬ 
 vation of what takes place in deep mines and in wells dug to a great 
 depth, leads us to believe that such a recourse would be found altogether 
 insufficient, even after dividing the tunnel by bulkheads into a number 
 of small sections. Should these fears prove well founded, it will not be 
 jDOSsible to approximately estimate the ultimate cost of such an under¬ 
 taking. The Engineers of tlie first committee of the Paris Congress, of 
 which Mr. Favre, the eminent engineer of the St. Gothard tunnel was 
 a member, were of the opinion that such a contingency would increase 
 the cost of the work by at least $20 000 000. In case the excavations 
 below the level of the sea were carried under water, the men and 
 machinery would have to work from scows, and the debris dredged and 
 deposited in dumping scows to be disposed of at the ends of the canal : 
 while all these operations of drilling, blasting, dredging and transporting 
 would have, necessarily, to be done within a width of from 66 to 100 feet„ 
 
321 
 
 according to the dimensions jDroposed for the tunnel by different parties. 
 Should it be found, as is apprehended by many, that the material met 
 with is not self-sustaining and that the tunnel will have to be totally or 
 partially lined with masonry walls resting on the bottom of the canal, the 
 jDroblem will become so complicated that a favorable solution may well 
 be despaired of. That work would have to be done by underpinning 
 from the crown of the arch, carried down to a depth of 28 or more feet 
 below the surface of the water, and for a distance of several miles. By 
 what methods it may be accomplished has not yet been explained. The 
 advocates of a thorough cnt are not disposed to admit that these contin¬ 
 gencies are likely to be met with, and even deprecate the idea that the 
 chances are just as much in favor of as against them. They will continue 
 to base their estimates on the assumption that the waters from filtration 
 will be no serious obstacle to the prosecution of the work to a depth of 
 28 or more feet below the level of the sea, as it may be readily disposed 
 of by pumping ; that the material will be self-sustaining and sufficiently 
 firm so that no lining of masonry, to speak of, will be needed to secure 
 the stability of the tunnel, and that an inclination of one horizontal to 
 ten vertical will be enough for the slopes of cuts 300 or more feet in 
 depth. 
 
 From the above considerations it seems to follow, that the bottom of 
 a canal across any portion of the Isthmus, should be placed sufficiently 
 high above the sea to obtain natural drainage, and that without this con¬ 
 dition the work may be considered impracticable on account of its im¬ 
 mense cost. This modification involves the necessity of three or more 
 locks on each side, which may not materially change the length of the 
 tunnel, but is sure to considerably reduce its cost by the elimination of 
 unknown quantities in this difficult problem. 
 
 The Nicabagua Route. 
 
 This line was carefully located from the Atlantic to the Pacific Oceans 
 by the United States Surveying Expedition, under Commanders Hat¬ 
 field and Lull, United States Navy, during the years 1872 and 1873, and 
 is fully described in the official rejmrts submitted to the Secretary of the 
 Navy in 1873. I was Chief Engineer of these expeditions from the com¬ 
 mencement of the surveys to the time the reports were completed, and 
 have subsequently visited the country on three different occasions, and 
 made extensive surveys in connection with this work, and the improve¬ 
 ments of the navigation of the river San Juan. I have, in fact, given 
 
 % 
 
322 
 
 close attention to tlie subject for a period of eight years. The estimates 
 of cost were based on the data obtained from a line of actual location. 
 Elevations of the ground were taken every 25, 50 or 100 feet ; and suffi¬ 
 cient cross sections, soundings, and gaugings of streams, borings of the 
 ground to the bottom of the canal, or until rock was met with, and such 
 other additional information as to building materials and means of com¬ 
 munication as were needed to arrive at a fair valuation of the probable 
 cost were obtained. Nothing was taken for granted, in the formation 
 of the project ; therefore, any changes of location introduced hereafter 
 by a more detailed final survey, will, with perhaps one exception, reduce 
 the original estimates. 
 
 This exception refers to the enlargement of all curves of less than 
 5 000 feet radius, objected to by some engineers, as too abrupt for a ship 
 canal. Distinguished officers of the United States Navy were consulted as 
 to the proper radii to be adopted, and they were of the opinion that 2 200 
 feet should be the minimum sufficient for the free passage of vessels 400 
 feet long. The following curves with the radii named were, in conse¬ 
 quence, located, viz., 1 of 2 200 feet, 3 of 2 500 feet, 11 of 3 000 ; 1 of 
 3 500 and 3 of 4 000 feet; all others have a radius of from 5 000 feet to 
 10 000 feet. 
 
 During the presentation of this route in the session of the 17,th May 
 of the Paris Congress, I was asked by M. Voisin-Bey, what, in my 
 opinion, would be the additional expense involved in increasing 
 the radii of the curves. I am reported in the printed proceedings 
 of the Congress, as saying in reply, that $28 000 000 would be the 
 probable cost demanded by the change. I do not remember what 
 my answer was to that question, but it will be apparent to any 
 one, that I could not have estimated so comparatively small addi¬ 
 tional work, at more than one-lialf the estimated cost of the whole 
 canal. I believe that $1 800 000 would be a liberal allowance under 
 the most unfavorable conditions. I have referred here to this subject 
 because a writer in the Bulletin du Canal Interoceanique, a paper published 
 in Paris, in the interests of the Panama scheme, has made a point of 
 that evident typographical or reporter’s error, and seems to doubt the 
 accuracy of some of the figures embraced in the estimate of the Nicaragua 
 route, which he could easily verify by computation from the elevations 
 given in the profile of the line, and the cross-section recommended. He 
 will also find in this paper an answer to his statements as to the cubical 
 
323 
 
 amount of excavation required for both the Nicaragua and the Panama, 
 line. Lake Nicaragua, the proposed summit level of the canal, is 110 
 miles long by 30 miles wide, and is situated at 107 xVo feet above the 
 mean level of the ocean. Several trial lines were surveyed from the lake 
 towards the Pacific, and on careful comparison of their relative merits 
 and elimination, it was decided that those connecting the mouths of tho 
 little streams, Lajas and Del Medio, with the port of Brito, presented the 
 greatest advantages on account of their moderate lengths and the com- 
 paratively low depressions by which they crossed the dividing ridge. 
 
 On a careful location, those lines were found to have an extreme 
 length from the lake to the Pacific of 18.52 miles and 16.33 miles respec¬ 
 tively for the Lajas and Del Medio routes. The divide was crossed at an 
 elevation above mean high lake of 43.78 feet by the first and 134 feet by 
 the second named lines. Considerations of better drainage and shorter 
 distance decided us in favor of the Del Medio route, and the estimates 
 of cost herein submitted are based on the data obtained from the survey 
 of the same. The difference in their locations is comprised between the 
 lake and a place called Las Serdas, where the level of the lake, if conti¬ 
 nued, would meet the Pacific Slope, thence to the Pacific, a distance of 
 8.33 miles, they form one and the same line. Should it be disclosed by a 
 more detailed survey that the difficulties presented by the Lajas line for 
 a good system of surface drainage can be overcome at a moderate 
 expense, that would certainly be the most advantageous of the two, on 
 account of a small extreme depth of cut through the divide and conse¬ 
 quent reduced cube of excavation and cost. 
 
 The level of mean high lake is 103.14 feet above high tide at the 
 port of Brito, an elevation to be overcome by ten lift locks 400 feet long 
 between gates, 70 feet wide and 10.31 feet lift, located in a distance of 
 eight miles. The ’depth proposed for the canal is 26 feet, and the width 
 at the surface of the water 150 feet in earth and 106 feet in rock, with 
 slopes of H horizontal to one vertical for earth and \ and 1 horizontal 
 to one vertical for rock. 
 
 The lake navigation extends from the mouth of the river Del Medio 
 to Porto San Carlos, the head of the Biver San Juan, a distance of 56.5 
 miles. The river San Juan is proposed to be made navigable by means 
 of four dams, and short canals and locks to pass them, for a distance of 
 63.02 miles to the confluence of the river San Carlos, the first large 
 tributary of the San Juan. At this point the canal leaves the river, and 
 
324 
 
 is located on its left bank for a distance of 26.90 miles, where it turns to 
 the north, and by an almost straight line reaches Grevtown, with a 
 further distance of 15 miles, or a total length of 41.90 miles from the 
 point where it leaves the river at San Carlos. This river it is proposed 
 to divert, so that its discharge into the San Juan shall be below the last 
 dam, and thus keep out of the canal its muddy and silt bearing waters. 
 
 t 
 
 Ten lift locks of 10.87 feet lift are estimated for this side, three of which 
 are located on the short canals around the dams. 
 
 The following table will show the position, and length, height, and 
 other particulars of the dams : 
 
 Location. 
 
 Distance from 
 Lake, in miles. 
 
 Length of Dam. 
 in feet. 
 
 Height above 
 bottom of 
 River, in feet. 
 
 Height water is 
 raised in front 
 of Dam, in feet. 
 
 1. Castillo. 
 
 37.34 
 
 940 
 
 21.01 
 
 18.87 
 
 2. Balas. 
 
 44.69 
 
 1 196 
 
 31.92 
 
 22.82 
 
 3. Machuca. 
 
 50.57 
 
 824 
 
 33.99 
 
 26.84 
 
 4. San Carlos. 
 
 66.81 
 
 1 000 
 
 30.97 
 
 23.87 
 
 The first three dams rest on rock foundation and rocky abutments. 
 The last one will rest on a hard and compact gravel bottom, and is 
 intended to be protected by an apron to prevent the undermining 
 effect of the fall. They are designed to be built of concrete, and 
 so constructed that the water in the river will not be raised until the 
 structures are completed in all their parts. This is expected to be 
 accomplished by leaving sluices in the dams sufficiently large to afford 
 a free passage to the river at high water, and to be closed by suitable 
 gates on the upper sides when the dam is ready to receive the pressure 
 intended. The river will be backed to the lake, the surface of which 
 will be raised from three to four feet, and I estimate that it will take 
 about four months for the river to reach the top of the first dam. 
 
 In the meantime the openings in the dams may be closed from the 
 lower side, and the material will have sufficient time to set, before it is 
 brought in contact with the water. 
 
 This method of construction will have other advantages in the con¬ 
 struction of the canal. 
 
 It will permit the dredging and rock excavations under water to be 
 done at a moderate depth, and allow the construction of the short 
 canals and lift locks around the dams, free from the high water of the 
 
 
 river. 
 
325 
 
 The total length of the line from Greytown, on the Atlantic, to Brito, 
 on the Pacific, is 181.26 miles, divided as follows : 
 
 Inland Canal. 
 
 Miles. 
 
 From the mouth of river Del Medio, at the lake, to Brito. 16.33 
 
 Short canal around Dam No. 1 across the river San Juan. 0.78 
 
 Short canal around Dam No. 2 across the river San Juan. 1.57 
 
 Short canal around Dam No. 3 across the river San Juan.^ 1.16 
 
 From Dam No, 4, below the river San Carlos, to 1 Gfi^tbiGl.. 41.90 
 
 Total length of canal. 61.74 
 
 Lake navigation. 56.50 
 
 Slack water navigation by the river San Juan,. 63.02 
 
 Total miles. 181.26 
 
 The following is a recapitulation of the estimated cost, viz. : 
 
 WESTERN DIVISION. 
 
 From the mouth of the River Del Medio to Brito, 16.33 miles. 
 
 Excavation and embankment.$16 787 566 
 
 Ten lift locks, 400 feet by 70 feet by 10.37 feet lift. 3 957 818 
 
 One tide lock, 400 feet by 70 feet by 9.0U feet lift.. 421 306 
 
 Drains, grubbing and clearing, &c . 514 087 
 
 Total for Western Division.$21 680 777 
 
 Middle Division, or lake navigation, 56.50 miles. 
 
 Dredging in mud and gravel and excavation in rock. $715 658 
 
 Eastern Division, from the Lake to Greytown. 
 
 Slack water navigation, 63.02 ; Inland Canal, 45.41 = 108.43 miles. 
 
 Excavation and dredging in the river. $5 076 030 
 
 Short canals around dams. 1 056 922 
 
 Excavation and embankment in canal, from Dam No. 4 to Greytown, 13 389 398 
 
 Dams Nos. 1, 2, 3 and 4. 1 543 526 
 
 Lift locks, from 1 to 10, inclusive. 3 093 160 
 
 Drains... 340 400 
 
 Diversion of San Carlos river. 283 578 
 
 -Grubbing and clearing (2,379 acres) ... 237 900 
 
 $25 020 914 
 
 Total for Eastern Division 
 
326 
 
 Recapitulation. 
 
 'Western Division.$21 680 777 
 
 Middle or Lake Divison. 715 653 
 
 Eastern Division. 25 020 914 
 
 Harbor of Brito. 2 337 739 
 
 Harbor of Greytown . * .. 2 822 630 
 
 Total.$52 577 718- 
 
 Add 25 per cent, for contingencies. 13 144 429* 
 
 Grand total. $65 722 147' 
 
 There are about 10 807 cubic yards of rock excavation estimated for,, 
 at the west side of the Lake, which would have to be blasted and dredged' 
 out at a depth of twenty-six feet below the level of the water in the 
 canal or twenty-two feet under water in the lake, at the time of doing the 
 work. This has been estimated for at $5.00 per cubic yard, which i& 
 thought a liberal price, considering that the rock is not a hard solid 
 mass, but boulders and blocks. Col. Childs’ estimate of the same work 
 in 1851, when our present means for doing this kind of work were un¬ 
 known, was from $2.50 to $5.00 per cubic yard. There are also 834 992; 
 cubic yards of rock excavation, and dredging in the river at depths vary¬ 
 ing from nine to fourteen feet, which has also been estimated for at $5.00 
 per cubic yard. Much of this material is loose rock, and the whole 
 would be removed before the river is raised by the dams. 
 
 The actual cost of some rock excavation in the River San Juan, at a 
 depth of six feet, done recently on a small scale and with scanty means 
 at hand, has been $2.50 per cubic yard of rock deposited on the banks ; 
 and I have been told by Mr. A. C. Rand of New York, that rock blasting 
 and dredging to a great depth (from sixteen to twenty-four feet,) is now 
 being done in the River St. Lawrence, at a cost of less than $5.00 per 
 cubic yard. 
 
 The total amount of excavation, dredging and embankment, exclu¬ 
 sive of the harbors estimated upon, may be given as follows: 
 
 Excavation in earth, cubic yards. 32 433 797 
 
 Excavation in rock, cubic yards... 14 435 477 
 
 Dredging in the lake and river. 4 855 935 
 
 Embankment.. 7 262 629 
 
 Excavation in rock under water. 845 719 
 
 Total cubic yards... 59 833 557 
 
327 
 
 Deducting from this total cube the embankment which will be con¬ 
 structed with the material proceeding from the excavation, at a small 
 additional expeuse over that for transportation, w^e will have 52 570 929 
 cubic yards as the total amount of excavation and dredging required, or 
 45 800 000 cubic yards less than the computed volume for the Panama 
 Canal, a niveau, with the same slopes and cross-section. 
 
 Computing the cubical contents according to the cross-sections pro¬ 
 posed for open cut, and a bottom width for the channel in the lake and 
 river of 100 metres (328 feet), as recommended by the Paris Congress, 
 we obtain a cube of earth and rock work of 53 793 982 cubic metres, or 
 70 663 000 cubic yards, an increase in the total amount of 10 947 998 
 cubic yards, as shown in the following table : 
 
 Cubical Contents of Excavation in Cubic Yards. 
 
 
 With Cross 
 Section of 
 Paris 
 Congress. 
 
 With Cross 
 Section for 
 Nicaragua 
 Line. 
 
 Increase. 
 
 Decrease, 
 
 Excavation in earth. 
 
 31 535 500 
 
 32 433 797 
 
 
 898 297 
 
 Excavation in rock. 
 
 10 393 537 
 
 14 435 477 
 
 
 4 041 940 
 
 Dredging in the river and lake. 
 
 18 209 722 
 
 4 855 935 
 
 13 353 787 
 
 Excavation in rock under water. 
 
 3 380 167 
 
 845 719 
 
 2 534 448 
 
 
 Embank rn ent,. 
 
 7 262 629 
 
 7 262 629 
 
 
 
 
 
 
 
 
 
 70 781 555 
 
 59 833 557 
 
 15 888 235 
 
 4 940 237 
 
 This increased amount of excavation is due to the enlargement of the 
 bottom width of the channel in the lake and river from 80 to 328 feet. 
 The width of 80 feet at the bottom of the channel, with slopes of six 
 horizontal to one vertical, I consider ample for all practical purposes. 
 In fact, a vessel drawing 24 feet would have a channel of 104 feet in 
 width, and for one drawing 20 feet the width would be 152 feet. I can¬ 
 not see why the channel in the river and lake, if properly marked, 
 should be much wider than in the inland canal, inasmuch as there is no 
 perceptible current in the lake, and that in the river will not exceed one 
 mile per hour after the improvements are completed. 
 
 I had occasion to call the attention of the first sub-committee of the 
 Technical Commission to the increased cube of dredging and rock exca¬ 
 vation under water, as herein, given, and suggested that by raising the 
 
328 
 
 height of the first dam across the river San Jnan one metre (3.28 feet), 
 more than two-thirds of the amount of excavation and dredging could be 
 dispensed with ; and also, about 360,000 cubic yards of rock excavation 
 between the lake and the Pacific. This change was not proposed in the 
 original project, because it involved an increase of 3.28 feet in the eleva¬ 
 tion of the summit level. This would not be justified by the small 
 saving resulting therefrom. 
 
 The objections made-to this route are: lift locks indispensable to 
 the solution of the problem, length of route, and poor harbors at either 
 end. 
 
 A canal without locks, that is, at the level of the ocean, is, no doubt, 
 a great desideratum , but its cost, under the most favorable circum¬ 
 stances, would be so great as to place it beyond the iDossibilty of a suc¬ 
 cessful commercial enterprise. The work, if ever done, will be under¬ 
 taken by private initiative and private capital, and these are not likely 
 to embark in an undertaking which does not promise sure and liberal 
 returns, however beneficial it may be to the world at large, and however 
 great a monument to mark the present age. Under the circumstances, 
 therefore, recourse must be had to locks, which, if properly constructed 
 and sufficiently supplied with water, will be found less objectionable than 
 has been supposed, The objections to locks are: loss of time in passing 
 through, and liability to accidents. With a moderate number of them, 
 properly constructed, the first objection will be found to be of little 
 consideration, and is snrely to be compensated for by the smaller tolls 
 charged in proportion to the reduced cost of the work, as compared to 
 other routes. 
 
 In pursuance of the system adopted in the design and computation 
 of this project, of not introducing doubtful elemants in the whole or any 
 of its parts, the lift of the locks was fixed at 10.37 feet on the Pacific 
 side, and 10.87 feet between the lake and the Atlantic. All of them 
 have been located so that they will rest on rock or stiff dry clay founda¬ 
 tions, and there seems to be no good reason why their lift should not be 
 increased to 15 feet, thereby reducing their number to fifteen. 
 
 The ground certainly offers all the facilities that could be desired for 
 the change. The engineers of the Paris Congress fixed the lift at 4 
 metres (13.12 feet) and the number of locks at seventeen. 
 
 General Weitzel, U. S. A., is now constructing a lock on the St. Mary 
 Falls Canal of 525 feet between gates, 80 feet wide and 18 feet lift. 
 Through this lock he proposes to pass a sljip in 11 minutes, as follows: 
 
329 
 
 Entering lock. 
 
 Closing gates. 
 
 Filling lock. 
 
 Opening gates. 
 
 Leaving lock 
 
 Total 
 
 14 minutes 
 1 
 6 
 
 1 
 
 n “ 
 
 11 minutes. 
 
 Tlie locks I have designed for the Nicaragua Canal would admit pas¬ 
 sage to a vessel in about 20 minutes, a time which can be much reduced 
 by enlarging the feeding and draining conduits. 
 
 I have the authority of Sir John Hawkshaw for stating that from 15 
 to 20 minutes would be ample' time to pass a lock of the dimensions 
 required for the canal, and the latter time has been adopted as a mean. 
 
 As to the liability to accident, it seems to me that, if properly con¬ 
 structed, and intelligently worked, no apprehension should be enter¬ 
 tained in that respect. Surely no such objections have been met with 
 in the dry docks in universal use, nor in the large canal locks in opera¬ 
 tion in this country and others that might be named. There are, on the 
 other hand, certain advantages possessed by a canal with locks over one at 
 the level of the sea ; for example, all, or the greater portion of the work 
 can be completed before the water is admitted into the canal; any por¬ 
 tion of the canal can be partially or entirely drained into the lower levels 
 to allow an examination or facilitate repairs in the channel or locks ; 
 a perfect system of drainage, independent of the canal, can be obtained 
 for the adjacent water sheds, and thus prevent floods from doing injury 
 to the canal. On the Nicaragua line, for instance, all the locks c*n the 
 Pacific slope, except the lower two, can be drained into the Rio Grande, 
 and similarly some of those on the Atlantic side. 
 
 The objection as to the length of the route may be answered by a 
 reference to the statements of distances given before. 
 
 It may be seen that the total length of canal navigation is 61.74 miles, 
 and there is no reason why a steamer should not travel in the lake and 
 river with her usual speed at sea. 
 
 The estimated time in passing by steamer, from ocean to ocean, is as 
 
 follows : 
 
 62 miles of canal, at 4 miles an hour.154 hours. 
 
 63 miles of river navigation, at 6 miles an hour.104 “ 
 
 564 miles of lake navigation, at 10 miles an hour.54 “ 
 
 21 locks, at 20 minutes each . 7 “ 
 
 Total.384 hours. 
 
330 
 
 Artificial harbors will have to be constructed at either end of the 
 canal. Plans and estimates have been prepared for the same, and they 
 have received the approval of many distinguished engineers, and were 
 accepted by the Paris Congress without criticism. It has been deter¬ 
 mined by careful observations that the sand bank obstructing the 
 entrance to the harbor of Greytown has been formed by the action of 
 the sea striking the sandy beach at an angle. It is proposed to con¬ 
 struct a breakwater or jetty, that, acting as a trap, will intercept the sand 
 moving along the coast from east to west. A channel will then be 
 dredged, under the lee of the jetty, to obtain an entrance to the bay, 
 the latter to be sufficiently deepened by dredging to satisfy the demands 
 of traffic. 
 
 At Brito, a breakwater, a pier, and dredging will be required to build 
 a harbor large enough to secure a smooth entrance to the canal, and 
 accommodate a number of vessels. With the lake, only 16 miles from 
 the sea by the canal, possessing all the advantages of an excellent 
 internal harbor capable of accommodating all the fleets of the world, the 
 harbor of Brito need not be large. 
 
 Building materials of all kind, such as wood, lime, stone, sand, etc., 
 can be obtained in great abundance, either on the line of the canal, or at 
 a convenient distance from it. With the river San Juan, the two lakes 
 and the river Tipitapa, which can be made navigable for vessels drawing 
 six or eight feet at a small expense, an easy and inexpensive line of com¬ 
 munication may be established through almost the whole extent of the 
 country by which men, provisions and materials can be transported to 
 any point along the proposed canal, from Greytowm to and through the 
 lake, and from the west coast of the latter to the Pacific, a distance of 
 16 miles, a railroad can be constructed at a small cost, or the present cart 
 roads can be extended and improved so as to answer the purposes 
 intended. 
 
 Sufficient data have not been obtained to_determine the annual mean 
 rain-fall of Nicaragua for a number of years ; but, from the observations 
 of Col. Childs in 1851, those of the surveying expeditions in 1872 and 
 1873, and the records of the College of Granada for the year 1875-1876, 
 we approximately fix at 52 inches on the Pacific slope, and 85 inches on 
 the Atlantic side. 
 
 The watershed of Lake Nicaragua is 12 250 square miles, which 
 includes the area of the lake itself, 2 700 square miles. Its outlet, the 
 
331 
 
 river San Juan, has a discharge of 12 453 cubic feet per second when at 
 its lowest stage in the month of May, and at high water the discharge is 
 20 500 cubic feet per second, these being the flow above the point where 
 the canal leaves the bed of the river, to be located on its left bank, and 
 thence to Greytown. Below the point referred to, the flow is consider¬ 
 ably increased by the accession of the waters of the rivers San Carlos, 
 Serapiqui, and other tributaries. Below the Serapiqui the flow is about 
 22 200 and 55 500 cubic feet per second in the dry and rainy seasons 
 respectively. 
 
 The Colorado branch of the river San Juan carries to the sea no less 
 than |~f of the volume of the San Juan, leaving but 3 L 0 of the flow to dis¬ 
 charge into the harbor of Greytown by the lower San Juan. Many have 
 suggested to close the Colorado by a dam, and thus throw the whole 
 volume of the river into the harbor as a means of scouring it out and 
 keeping its entrance open, but this plan has been thought, after much 
 consideration of the subject, to be impracticable and inefficient. 
 
 Earthquakes are rather frequent in Nicaragua, but are only slight 
 shocks that never have done any injury to life or property, nor altered 
 in the least the level of the waters in the lakes, rivers, wells, etc. Works 
 built by the Spaniards over one hundred years ago, such as masonry 
 dams across rivers, fortifications, indigo vat', cisterns and the like, are 
 to-day in an excellent state of preservation. 
 
 Conclusion. 
 
 From the above statements and considerations it seems to follow— 
 
 1st. That however desirable a canal at the level of the sea, partaking 
 of the nature of a strait may be, to better satisfy the demands of 
 trade, its execution, either with or without a tunnel, presents so many 
 difficulties and doubtful elements as to place its probable cost out of the 
 range of a successful commercial enterprise. 
 
 2d. That a canal with locks can be so constructed as to satisfy all the 
 requirements of ocean navigation, at a cost within the possibility of a 
 private undertaking, with reasonable expectations of liberal returns and 
 without overtaxing the commerce of the world intended to be benefited 
 thereby. 
 
 3d. That while a canal with locks seems to be practicable, via both 
 Panama and Nicaragua, the latter route possesses greater facilities for 
 the execution of the work at a reduced estimate of cost based on suffi- 
 
332 
 
 cient information to eliminate unknown elements, which might materially 
 so alter the conditions of the project, as to cause painful disappointment 
 to take the place of long deferred hopes and cheering expectations. 
 
 And furthermore, that the geographical position of Nicaragua is more 
 favorable to the United States, whose commerce will contribute more 
 than that of any other nation to the business of the canal, while it will 
 afford as great commercial advantages to foreign nations, as other routes 
 more to the south. 
 
 Finally, I would state that, while attempting to confine my remarks 
 upon this interesting subject (upon which volumes have been and may 
 yet be written) to as limited a space as possible, I have treated it more 
 at length than was originally intended, and close with the hope that 
 conciseness, if at all attained, has not been at the sacrifice of clearness 
 in the presentation of the points touched upon. 
 
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