October 14, 1887.] 



SCIENCE. 



land will probably be very narrow. The necessar)' land will be 

 granted by Costa Rica to the association. The canal route follows this 

 deep basin to the western slope of the dividing ridge between the 

 creek San Francisco and the river San Juanillo, 12.55 miles from 

 the dam, and 19.4S from Greytown. Beginning at the eastern ex- 

 tremity of this basin, the canal cuts through the dividing ridge, the 

 summit of which is 2S0 feet above sea-level, and in a distance of 

 14,200 feet, in which the average depth of the cutting is 119 feet 

 above the water in the canal, strikes the eastern slope of the 

 divide. This point is on the eastern terminus of the summit-level 

 extending from the upper lock on the Pacific slope, a distance of 

 144.8 miles. Here it is proposed to car\'e in the solid rock, at the 

 end of the deep cut referred to, the upper lock of the eastern branch, 

 and drop the level of the canal 53^ feet. The ground thence de- 

 scends gradually to the next lock, .87 miles below, where another 

 drop of 27 feet takes place ; and the canal for a distance of about 

 three miles is cut through a broad, slightly inclined valley to the 

 third and last lock. This lock lowers the canal to the level of the 

 sea, and from here it takes a direct course through the alluvial 

 plains of the San JuaniUo to the harbor of San Juan del None, or 

 Grejtown, a distance of 11.55 miles ; from the last lock to Grey- 

 town on the east, and to Brito on the west side, the canal is en- 

 larged, forming extensions of the harbors, where vessels can pass 

 each other without detention. Ample provision has been made to 

 protect the canal from surface drainage. Two basins are proposed 

 at each lock where vessels can wait or pass each other without 

 delay. The canal is proposed to be So feet wide at the bottom in 

 deep cuts, and 120 feet in the terminal cuts and other enlarged sec- 

 tions ; the width at the surface of the water being 80 feet in deep 

 rock cuts, and 184, 2S8, and 342 feet at other points. The locks are 

 estimated 650 feet long between mitre sills and 65 feet width of 

 chamber. The estimated time of transit from sea to sea, on the 

 basis of a speed of 5 miles per hour in the canal proper, 8 to 10 

 miles per hour in the river and lake, and 45 minutes' detention at 

 each of the seven locks, is 30 hours. Allowing but one vessel to 

 each lockage, 32 vessels in one day, or 11,680 in one year, can be 

 passed through the canal. Breakwaters and dredging will be re- 

 quired at the harbors of Brito and Greytown to secure a free 

 entrance. 



It is estimated that the canal and its accessories can be com- 

 pleted in six years ; and its cost, including 25 per cent for contin- 

 gencies, is put down at $64,043,697. The estimates are the result 

 of an actual instrumental location of the entire line, and the surve}"s 

 have been conducted with great care, and sufficiently in detail to 

 insure a close estimate of cost. 



The characteristic features of this location as compared to that 

 ■of 1S72-73 are the great extension of the summit-level eastward, 

 which practically e.xtends Lake Nicaragua to the divide between 

 the San Francisco basin and the San Juanillo, by the high dam at 

 Ochoa, and the embankment near the confluence of the San Francisco 

 and San Juan, and the difference of the location of the upper part 

 of the western di\-ision. Commander Lull recommended the Rio 

 del Medio route, though it required cuttings of 134 feet, on account 

 of better natural surface drainage, which is of the greatest impor- 

 tance for the stability of the work in a countr\- \\-ith hea\y rainfalls. 

 On that line no water-course of considerable size would be taken in 

 the canal, and, as its watershed is quite small, no fears were enter- 

 tained of damages from freshets. On the Rio Lajas route the Rio 

 Grande, a mountain stream of extensive and rapidly inclined water- 

 shed and precipitous channel, with a maximum flow of about 10,- 

 000 cubic feet per second, had to be passed. This difficulty has been 

 overcome by Menocal by diverting it into the Juan Davila, a tribu- 

 tary of the Rio Lajas. 



Dr. Polakowsky (Peterntann's Mitteilungen. 1887, p. 138) raises 

 several objections against this project, which, however, are not well 

 founded. He says that it will be necessary- to retain the present 

 level of the San Carlos, as it would flood extensive parts of Costa 

 Rica. This, however, cannot be true, as its course is ver\' rapid, 

 and as the lower part of its channel passes through a hillv countr)-. 

 Neither will the banks of the San Juan be flooded to any consider- 

 able extent, as may be seen from the accompanpng map. The ex- 

 tent of land owned by private parties and required for the canal is 

 very trifling, and therefore no considerable additional cost will be 



occasioned by this item. The lands belonging to the state of Nicara- 

 gua will be given to the association without any compensation 

 whatever. Besides the works belonging to the canal proper, the 

 association is obliged by contract with the Republic of Nicaragua 

 to establish a communication between the part of the San Juan not 

 used for canal purposes and the canal by means of locks suitable 

 for the navigation of ships of 6 feet draught, and another canal be- 

 tween Lake Managua and the lower part of the Tipitapa of suflS- 

 cient dimensions to admit the passage of vessels drawing 6 feet, and 

 of 1 50 feet length. The difference in level between the lakes is 

 22.34 feet. The river Tipitapa is shown in our map : it is full of 

 rapids, and has a fall of 13 feet above the bridge of Tipitapa. 

 This canal will be the propert)- of the government. 



Besides the land necessary- for the construction of the canal, con- 

 siderable land-grants are ceded to the company. On the left bank 

 of the river San Juan from the Atlantic to Castillo Viejo it will re- 

 ceive alternate lots of three miles frontage and sis miles in depth ; 

 from Castillo to the lake, on the south side of the river, lots two 

 miles frontage and two miles depth ; all along the south shore of 

 the lake to the mouth of the Rio Lajas, lots of one mile square ; on 

 the northern bank of the Rio San Juan above Castillo, lots of three 

 miles frontage and four miles in depth ; and, continuing on the east 

 shore of the lake as far as the river Tule. lots of two miles frontage 

 on the lake and two miles depth are ceded to the company. Fur- 

 thermore, it will receive forty lots of the existing public lands, each 

 four miles frontage by five miles deep. 



Though Menocals plan is the result of frequent and thorough in- 

 vestigations, it is not considered as final, but the Canal Association 

 intends to have the routes, and particularly the divides, resun'eyedin 

 the coming winter. Operations will be taken up in the present 

 month. So far the geological features of the countr}- traversed by 

 the canal are still insufficiently known, and to these particular at- 

 tention will be paid. From the specimens collected by Lull's and 

 Menocal's expeditions, it appears that metamorphic rocks form the 

 foundation of the eastern part of the country. Overhing these, vol- 

 canic lavas, such as very compact basalts, andesites, and rhyolites, 

 were found. Borings will be made in all the localities where cuts 

 are proposed. Particular attention wiU be paid to the eastern 

 di\ide, as it is considered desirable to avoid the cutting of 119 feet 

 above the water of the canal, if possible. The results of these sur- 

 veys and borings will be laid before the leading engineers of North 

 America and Europe, and not until then the final route will be 

 adopted. It is hoped that thus unforeseen difficulties will be 

 avoided. 



The climate of Nicaragua is an important consideration, particu- 

 larly while the canal is being constructed. The western part is un- 

 doubtedly healthy, while malaria prevails in the swampy delta of 

 the San Juan. The following description of the climate by Von 

 Franzius will be of interest. 



In the north-eastern part of Central America the north-easterly 

 trade-winds are the rainy winds from November until Februar)". 

 They lose their humidity on the eastern slope of the mountains, and 

 reach the south-west side as dry winds. Particularly from Novem- 

 ber to January the trade-winds bring rain on the north-east side, 

 in February and March rain is scarce, and in April there is none 

 whatever. In the beginning the rain is even carried across the 

 mountains to the south-western slope, where it extends a consider- 

 able distance down the valleys. Particularly in the saddles of the 

 mountain ranges the rain extends south-westward. In November 

 and December the rainy spells sometimes last for tw-o or three 

 weeks. The}- are called ' Na\idades.' At the same season, when in 

 October and November the north-easterly trade-winds make their 

 first appearance and bring the first rain on the north-east side, the 

 rainy season is at an end on the south-west side. The sky is 

 clearing up, and the trade-winds begin to blow, at first squally, 

 later on as a strong breeze. There are no thunder-storms during 

 this season, which is called ' Verano." The mountains are seen 

 through a blue haze, while the air is very transparent and clear 

 during the rainv season. The short period of calm weather crosses 

 Central America twice, — first in March following the receding trade- 

 winds, and then in October. The trade-winds reach the northern 

 parts of Central America about the end of September. In the be- 

 ginning of October they begin to blow in Guatemala, about the end 



