332 



ENGINEERING. 



miles in length. The most important tunnel 

 is that of Beguds, 3,000 feet long, and changing 

 direction three times. Two branches leave 

 the main canal, one 7*5 miles and the other 4 

 miles long, both of them passing several bridges 

 and tunnels. Of these the first has a capacity 

 of 28 cubic feet, and the second of 21 cubic 

 feet a second, the remaining 92 cubic feet 

 passing on in what is still regarded as the main 

 canal until it reaches Gairaret, where it ends 

 in a skillfully arranged cascade, the water fall- 

 ing into a large basin, the outlet of which is a 

 third branch, which supplies irrigating canals 

 and large reservoirs along the banks of the 

 Paillon. Every advantage is taken to afford 

 motive-power for machinery, as this branch de- 

 scends toward the river-level, and the taste of 

 the landscape-gardener has been joined to the 

 skill of the engineer in utilizing every pound 

 of pressure. Frequent cascades and rapids 

 meet the eye. The third branch is to be con- 

 tinued beyond the Paillon, but this work is 

 still in the future. A " high service " is organ- 

 ized by means of turbine-wheels driven with- 

 out waste of water at certain advantageous 

 points, and by this means water is pumped up 

 to the highest desired levels. The whole work 

 has been done in the most careful and thor- 

 ough manner. The canals have an average 

 gradient of 1 in 2,000 in the open portions, 

 and 1 in 1,000 in the tunnels and aqueducts, 

 and everywhere precautions have been taken 

 to provide outlets in cases of sudden floods or 

 unexpected pressures. The water now fur- 

 nished for household purposes in the city of 

 Nice is understood to be of excellent quality, 

 cheap and abundant. The chief engineer of 

 the works was M. Grisel, under whom were, of 

 course, several sectional engineers. Of these, 

 MM. Duplay and Walter (the latter since dead) 

 especially distinguished themselves. The reve- 

 nues of the company are as yet insignificant, 

 but it is estimated that the income from sub- 

 scriptions for purposes of irrigation will event- 

 ually be such as to afford a fair interest on the 

 investment. 



The New Croton Aqueduct. This aqueduct was 

 fully described in the " Annual Cyclopaedia " 

 for 1884, and the details of the work are now 

 being carried out substantially as there given. 

 At this writing, about 25,000 feet of the tun- 

 nel are completed, and the work of excavation 

 is progressing at the rate of about one mile a 

 month. The great dam at Quaker Bridge has 

 not yet been definitely determined upon. 



Aqueduct at Venice. Until the sixteenth cent- 

 ury Venice depended for drinking-water upon 

 rain-cisterns. Subsequently a canal brought a 

 supply from the Brenta to the nearest main- 

 land, whence the water was transported in 

 boats having a capacity of about 530 gallons. 

 This method was continued until recently, when 

 the city authorities adopted the plans of French 

 engineers, and the Venetian Societe de Con- 

 struction took the work in charge, and began 

 operations early in 1880. The works were 



completed, and the formal inauguration took 

 place with the opening of a fine fountain in 

 the center of the plaza of St. Mark, on July 23. 

 An aqueduct 16 miles long brings the water 

 to filtering-beds and an immense reservoir, 

 whence it is introduced into the city by means 

 of siphons and subterranean pipes. 



The James Watt Dock. On May 1 the great 

 dock at Greenock, Scotland, was virtually fin- 

 ished, and the water turned on. This forms, 

 in connection with the Garvel Graving Dock 

 and other works, an artificial harbor system 

 probably not surpassed anywhere in the world. 

 The average depth of excavation for the Watt 

 Dock was about 47 feet, the material being 

 mainly sandstone rock and bowlder clay. Some 

 of the sandstone was suitable for the rough ash- 

 lar, or " sneckled " rubble of the quay-walls, 

 and the walls themselves were largely hewed 

 out of the solid rock left "in place." In the 

 dock basin 800,000 cubic yards had to be 

 blasted. All the excavated material was used 

 near at hand, part of it on a railway embank- 

 ment. The major portion was used in the 

 formation of a fine tidal harbor, which will 

 be 4,000 feet long by 700 feet wide, with a 

 depth of 28 feet at mean low water. It was at 

 first proposed to carry the excavated material 

 to the mouth of Loch Long, at an estimated ex- 

 penditure of $350,000. The harbor construction 

 has cost $100,000, and is worth at least $250,- 

 000. In other words, Mr. W. R. Kinipple, the 

 engineer of the Greenock Harbor Trust, has 

 saved the Trust $250,000, and made them a 

 present gratis of a harbor that must prove 

 quite as valuable as the great dock itself. Such 

 is the mission of the conscientious and able 

 engineer. The Watt Dock is 2,000 feet long. 

 The width for half its length is 300 feet. The 

 remaining portion (which is divided by a tongue 

 or jetty 50 feet wide, designed to increase the 

 available mooring area) is 350 feet. The depth 

 of water is 32 feet. There are two entrances 

 from the two adjacent tidal harbors, each 75 

 feet wide, with a depth of 32 feet on the sill at 

 high water. The surface area of the dock is 

 14| acres, and the length of quay nearly li 

 mile. The dock -walls terminate in curved 

 " toes " of brick and concrete, founded 2 to 2| 

 feet below the bottom of the dock. From the 

 top of these to near low-water mark, sand- 

 stone is used. Thence upward to the coping 

 the facing is of finely dressed granite backed 

 with rubble concrete and Portland cement, 

 and finished with massive granite copestones. 

 The retaining caissons are Mr. Kinipple's pat- 

 ent, and were constructed by the Messrs. I 

 caid, of Greenock, at a contract price of $135,- 

 000. To the top of the caissons lowering o 

 folding bridges are attached, to provide for 

 roadways, etc. Under one of the entrances 1 

 the dock is a subway, so that transit is easy 

 from one pier-head to the other when the en- 

 trance is open. The caissons, it is said, can l.( 

 hauled out of the way or replaced in less than 

 five minutes, by a small hydraulic engine pro- 



