We herewith present to our readers a view of a portion of one of the most remarkable works in hydraulic engineering of modern timal. . It is called the “ Canal de Isabella II.,” and was originally designed to supply the city of Madrid with water. It has, however,also been employed for inrigating the vegetable gardens in the environs jg.f the, Spanish capital. Thiseanal and the magnificent works connected' with it were sanctioned by the “ Spanish Government in 1851, and the work was broughtto completion in 1858. Its cost was 57,897,368 francs, over eleven and one half . millions of dollars in designed thig im- DonlEiucio del Yal- 113, engineer-in-chief to the Spanish Government. For his services he received the honor of the order ofCharles the Third. He was assisted by the present engineer of the works, Don Jose de Morer. The total length of the canal is over forty-seven miles. In this length there are seven miles of subterranean gal- leries,four thousand six hundred feet of aqueducts,andeight thousand six hundred feet of siphons. There are also many remarkable trenches, retaining walls, etc., and excepting the aqueducts, the entire canal is archedover. The water is brought from the river Lozoya, where it emerges from the Guadarama Mountains to the north of Madrid. A dam, ninety-eight feet in hight, is erected at this point, abutting on the rocka which form the banks ot the river. This is built of ,cut stone, and the lake formed by it contains one hundred millions cubic feet of water. The two principal siphons are those of Guadali)): aIl-d <1oa$1, The latter is the subject of the engraving which ac. <companil!l this sketch. It is about four thousand six hundred feet in length. The transw-eise section <rf the canal has an area of about •twenty squ,ar».feet, and it discharges about six millions six lJ,uadr«d thousand cubic feet of wILter per-day. Only about BEDOitAL SIPHON OF THE “ CANAL DE ISABELLA II," one fifth of this supply is used for the towlf service, the rest being employed for irrigation. 1'hB wPoter, o:p. emerging f?om the lake, passes through a tunnel, and between this tunnel and the city of Madrid there are thirty-one tunnels, thirty-two aqueducts—amo\lg which ILre some about ninety feet in hight and nearly three h1lndred feet in lengthand three great siphons, besides the enormous one shown in otl-r engraving, employed to carry the canal aCross valleys, eacn of which is composed of four pipes abo'Q,t SPAIN. three feet in diame ter. The water for purposes of. irrigation is drawn off before the canal finally discharges itself into the reservoir del Campo Guardias. which occupies the highest ground in the vicinity of Madrid. The lands irrigated comprise four thousand four hundred and forty-six acres. Tha town service <:.Pmprises, over sixty miles of cart-iron pipes, and over forty- five miles of subterranean canals lined with brick and cut stone. The, smallest of these are sufficiently high for workmen to stand upright. In addition to the private service in the city, thirty-five public fountains are sup plied, and three thousand' orifices for irrigati(l . -and ex- tinctiol). of fires. Of alt, the jue- ducts, those ,of La Sima and Colmcnar- .the m«fe£»ote- Worthy, • It was first intended' to carry.the canal at. ,La Sima across in a- siphon like those'!described above, and';jtlne was commenced inaccord- ance witp, , that design, but, it was subsequently decided to erect an aqueduct. This aqueduct is two hundred and fourteen feet long and eighty three feet high. It has an arch. at the bottom of fifty-five feetspan,abovewhich are seven arches of about twenty-four ft. span. The Colmenarejo aqueduct is three hundred and eighty. four feet long and sixty feet high. This aqueduct has fifteen semicircular arches of over twenty-five feet span, built of cut limestone and granite. Previous tothe erection ' of these works the city of Madrid depended for its water supply partly on wells and. partly on a smallstream which flows into the town; the water was raised by two large pump- The works we have described, ing engines at g1.'Caexpense. now furnish water at no cost except the interest on the of the woJ;l!:s and the maintenance of repairs. The head is ample to throw water over the highest buildingsl p' the city. Hitherto the construction of such works has,heen opposed by the miUtrg upon streams, who were reluctant to surrender their rights unless exorbitantly paid. Under the new law J,'egulating such matters, they are compelled to sell their. privileges ad a priee fixed by appraisal.