590 



NA TURE 



[October 21, 1897 



other places. This cutting, although it provided an out- 

 let for the flood water, gave only partial relief to the 

 drainage of the city, the general level of which is about 

 6| feet above the surface of the water in Lake Texcoco, 

 into which the main outfall discharges; while the water 

 in the other lake varies from 4 to 13 feet above the 

 pavement of the streets. When the level of the water is 

 raised in the lake, it is backed up the sewers into the 

 city, and the whole surface of the ground has become 

 saturated with sewage. 



For a very long period, schemes were under considera- 

 tion for effectually draining the city, and works were 

 begun from time to time, and then suspended, and it was 

 not until 1849 that a definite plan was determined on. The 

 works recently completed were commenced in 1866, but 

 owing to the revolution were stopped, and remained in 

 abeyance until 1885. The City Council then contracted 

 a loan for 2,400,000/., which, however, was expended 

 without finishing the work, and the Mexican Govern- 

 ment had to appropriate further funds for the purpose. 

 The contract was first let to an American firm, but was 

 subsequently taken out of their hands and completed 

 by Messrs. Pearson and Son, the well-known English 

 contractors. 



The works now carried out consist of a canal starting 

 at the city gates, and running 22 miles to the mountain, 

 through which it passes by means of a tunnel 6| miles in 

 length and 14 feet in diameter, driven principally through 

 sandstone, and at the highest point being 300 feet below 

 the surface. The canal varies in depth from 17 feet to 

 65 feet, and is 20 feet wide at the bottom. 



This canal will take the storm water and sewage of the 

 City of Mexico, and discharge it into the Valley at 

 Tequixquiac. It will also control the height of the water 

 in the lakes, but not drain them. The cutting of the 

 canal involved a considerable amount of structural work 

 where it crossed the railways and high roads, and in 

 providing for the drainage of the district through which 

 it passes. 



While the work above described consists of works for 

 " unwatering," another project of great magnitude recently 

 carried out is for rendering land fertile by bringing water 

 on to it. There are evidences to show that irrigation has 

 been practised in Central America before the time of his- 

 torical record. When the Spanish invasion of Mexico 

 took place, the Indian inhabitants were dependent on 

 irrigation for raising the crops of grain and cotton which 

 they cultivated, and Mexican landowners have continued 

 to follow in many cases the methods of their prede- 

 cessors, but in others have brought to bear on their 

 operations the principles of engineering science, and 

 have applied them to very large tracts of land which 

 otherwise would have remained practically barren. In 

 some cases the streams have been dammed and the water 

 carried on to the land by irrigating channels, while in 

 other cases the water is raised by pumps driven by 

 windmills or steam power. The crops grown on these 

 irrigated lands consist of corn, cotton, tobacco, oranges, 

 and other fruit. The description given below applies to 

 the largest enterprise yet undertaken, but which is typical 

 of many others. 



The great plain of Northern Mexico is bounded on the 

 east and west by the sierras of the Pacific and Gulf 

 coasts, and is situated at a height of 4000 feet above the 

 level of the sea, covering an area of about 240,000 square 

 miles. This basin receives the drainage from several 

 rivers which run into large shallow lakes, whence the 

 water gradually evaporates during the dry season. ,The 

 alluvial matter brought down during long periods has 

 completely filled some of these lagoons with a deposit of 

 the finest alluvial soil of unknown depth. About fifty 

 years ago tracts of this fertile land bordering on the 

 river Nazas, and covering about 250,000 acres, were 

 brought under cultivation by a system of ditches and 



NO. 1460, VOL. 56] 



banks, and on this was produced a great part of the 

 cotton grown in Mexico. 



Separated from the river by a tract of 30 miles of 

 barren desert land, is one of the richest districts in Mexico, 

 being the site of an ancient lake called Tlahualilo, but 

 until the present enterprise was undertaken the con- 

 veyance of the water from the river to this land presented 

 an obstacle to its cultivation. In 1889 a company was 

 formed, and works carried out for irrigating this district 

 extending over 210 square miles. The concession of the 

 water rights having been obtained, a dam was constructed 

 across the river Nazas, and the water conducted from 

 there across the desert by means of a canal, 39 miles in 

 length, and 72 feet wide at the bottom, and 61 feet deep, 

 to the entrance of the area to be irrigated, when it 

 branched off into two other canals, one 15 miles and the 

 other 13 miles long. These side canals were prolonged 

 down each side of the basin, meeting at the further 

 extremity, and enclosing an area of 57,000 acres. The 

 irrigated area was laid out in separate tracts or " sitios," 

 containing 4338 acres, the area controlled by each 

 subsidiary drain being 134 acres. The total length 

 of the main drains and ditches was 479 miles. The 

 difficulties encountered in carrying out this work 

 were very great. For 25 miles of the distance 

 along which the main canal was carried, all the 

 water for the men and animals employed had to be 

 carted, as well as the supply of food for the 2000 to 

 3000 Indians employed. On the completion of the 

 canal, on the "sitios" were erected the buildings 

 necessary for forming villages, with houses for the men 

 and their families engaged on the land, together with 

 magazines, farm buildings, storehouses, and reservoirs 

 for water, each " sitio " being placed under the control 

 of a separate manager and staff. At the central 

 station, in addition to the above, were erected a steam 

 cotton-gin and press, oil mills, soap factory for utilising 

 the oil product, and electric light plant. There were also 

 built a church, public schools for the children, a market, 

 hospital and other conveniences for the welfare of the 

 population. The number of steam-engines employed on 

 this estate aggregate over 300 horse-power, the fuel for 

 which consists principally of the hulls of the cotton-seed 

 and the wood derived from clearmg the bush. The 

 engines and machinery are operated by native labour, 

 the peons being found quick and apt in acquiring 

 mechanical knowledge. 



The result of this enterprise has been very satisfactory, 

 and six years' experience shows that irrigation when 

 applied to fertile land in a systematic manner renders 

 agriculture in the climate of Mexico highly remunerative, 

 and reduces the uncertainty and hazard of obtaining 

 crops to far less proportions than where their successful 

 cultivation is dependent on rainfall. There is a very 

 large area of similar good land not used in Mexico 

 owing to lack of water, the risk of depending on the 

 rainfall being considered too great. 



RIDG WAY'S BIRDS OF THE GALAPAGOS.^ 



IT was Darwin, in his " Naturalist's Voyage," who first 

 called attention to the peculiarities of the fauna of 

 the Galapagos, and urged the importance of its more 

 accurate study. Wallace, in "Island Life," has devoted 

 a whole chapter to the discussion of the curious pheno- 

 mena of distribution which it presents, and which are 

 in no case better exhibited than in the class of birds. 

 The National Museum of Washington has of late years 

 acquired a very fine series of Galapagan birds, principally 

 through the exertions of the naturalists of the Albatross 

 in 1888 and 1891, and from the collections made by 



1 " Birds of the Galapagos Archipelago." By Robert Ridgway. R.U.S. 

 N.-it. Mus. xix. Pp. 459-670. (Washington, 1896.) 



