252 



ENGINEERING IN 1892. 



arch of long radius covered by the beam-and- 

 brick arch construction familiar in modern 

 buildings. The discharge is into a silt basin and 

 through 20 pipes of 36 inches diameter each. 

 The silt basin is provided with traps, although 

 the pipes are as much as 8 feet below tide level. 

 It is said that this is the third largest of the 

 working sewers in the world, that of Washing- 

 ton being 20 feet in diameter, while the great 

 sewer of Paris is 18 feet high and 17 feet wide. 

 The Cloaca Maxima of the Romans occupied a 

 total cross area of 30 x 15 feet. It is believed 

 that this sewer will remove a considerable danger 

 which threatened a part of the inhabitants of 

 the city, and the rush of comparatively clean 

 water will no doubt tend to clear out the Gow- 

 anus Canal, at present by no means an attract- 

 ive feature of the Brooklyn water front. L. 

 Russell Clapp and David Brower, assistant city 

 engineers, were in charge of the construction, 

 under Robert Van Buren, chief engineer. 



The Water-Power of Niagara Falls. This 

 vast work is now nearly approaching realization. 

 The enormous forces that go to waste over Ni- 

 agara have always offered fascinating problems 

 to the utilitarian mind, and as early as 1725 a 

 rude saw mill was erected at the " awful brink " 



LOWER TUNNEL, NIAGARA FALLS. 



by some pioneer who could not bear to see such 

 a superb water power unemployed. This gave 

 way before the march of tourists as the falls be- 

 came a center of interest, and although the sub- 

 ject of utilizing the power was often considered, 

 nothing was done until 1873, when the present 

 canal was made, affording about 6,000 horse 

 power and driving several mills. This was a 

 mere trifle compared with the full head of water, 

 and the elaborate plans since perfected are now 

 nearly carried out. Various estimates have been 

 made as to the total power of Niagara Falls, but 

 the lowest places it at several millions of horse 

 power, and it is believed that it is not beyond 



proof that its power is twice as great as that of 

 all the combined steam and water power at pres- 

 ent employed in the United States. The illus- 

 tration on page 253 shows the main features of 

 the work. The great tunnel is 7,250 feet long, 

 forming what is known in ordinary works as the 

 tail race. Its outlet is in the river just above 

 the water level, under the cliffs below the town 

 of Niagara. The intake end is on the river bank 

 above the town, where the company own a large 

 tract purchased for the purpose. This is laid 

 out for mill sites and for the required surface 

 canals through which water can be led to the 

 different wheel pits, all of them being connected 

 by lateral tunnels with the main discharge tun- 

 nel. The cross section of the tunnel is of the 

 ordinary horseshoe shape, 19 feet wide and 21 

 feet high inside of the brickwork. The cross- 

 sectional area is 386 square feet, but this does 

 not express the total amount of excavation, the 

 timbering and brickwork calling altogether for 

 a cross-sectional area of 522 square feet. The 

 sill of the tunnel at its discharge opening is 205 

 feet below the sill of the head gate at the en- 

 trance above the falls. Of this about 140 feet is 

 practically available, the difference in perpen- 

 dicular height being taken up by margin of 

 clearance and for the necessary in- 

 cline and lateral tunnels, which is 

 generally at a grade of 36 feet to 

 the mile. Abrasion is measurably 

 guarded against by lining the tun- 

 nel with heavy cast-iron plates, as 

 it is not believed that brick- work or 

 masonry could stand the wear and 

 tear for any length of time. The 

 illustration shows how the main 

 stream of water is led to the head 

 of the turbine trunk, whence its 

 fall is perpendicular through about 

 140 feet of pipe. The kind of tur- 

 bine best for the purpose, and the 

 method of setting the wheel, called 

 for careful investigation, and it was 

 eventually determined that, in order 

 to decrease the wear on the bearings 

 of the wheel shaft, the water should 

 be delivered on the under side of 

 the wheel. A commission was sent 

 to Europe to examine plans for the 

 generation of power by turbines, and 

 prizes were offered for the best de- 

 vices. The two firms receiving the 

 highest award offered two projects 

 for the utilization of 125,000 horse 

 power and its electrical distribution ; 

 these are the adoption of the well- 

 known Girard turbines, with a unit of about 

 2,500 horse power for each wheel. The com- 

 pany expects to make its contract with the city 

 of Buffalo for lighting the city, about 3,000 

 horse power being required for the purpose. If 

 this enterprise proves successful, it is difficult to 

 say where the transmission of power by electri- 

 city will end. It is by no means unreasonable 

 to anticipate that, with such an enormous power 

 as Niagara available, means for lighting cities 

 hundreds of miles away may be attained. 



Masonry Dam, Austin, Texas. The great 

 Colorado river of the South has been dammed 

 with a view to a water supply for the capital of 



