36o 



NA TURE 



[August ii, 1892 



Frankfort, a distance of io8 miles, and used for lighting and 

 driving a motor. The current was obtained at low tension, 

 transformed up to a tension of 18,000 to 27,000 volts for trans- 

 mission, and then transformed down again for distribution. The 

 loss in the conducting wires ranged from 5 horse-power when 

 the turbines worked at 100 horse-power, to 25 horse-power 

 when the turbines worked at 200 horse-power. The efficiency 

 of dynamo, two transformers, and line ranged from 68 to 75 per 

 cent., a remarkably satisfactory result. 



There can be little doubt that if efficient and durable trans- 

 formers can be constructed, they do give a considerable advan- 

 tage to an alternate-current system. To an ordinary engineer 

 it appears also that the system of producing current at a low 

 tension in the dynamo, and using it at low tension in the motors, 

 permits the construction of dynamos and motors more mechani- 

 cally unexceptionable than those worked at high voltage. 



I have spoken of the growth of a demand for power 

 distributed in a convenient form in towns. The power 

 distribution in London, Manchester, Birmingham, and 

 Liverpool by pressure water, and that by compressed air in 

 Paris, shows how rapidly, when power is available, a demand 

 for it arises. A striking instance may be found in the small 

 town of Geneva. 



In 187 1, soon after the completion of the earlier system of 

 low-pressure water supply. Col. Turrettini applied to the muni- 

 cipal council to place a pressure engine on the town mains for 

 driving the factory of the Society for Manufacturing Physical 

 Instruments. The plan proved so convenient that nine years 

 after, in 1880, there were in Geneva in water-motors supplied 

 from the low-pressure mains, using 34,000,000 cubic feet of water 

 annually, and paying to the municipality nearly ;^2000 a year. 

 The cost of the power was not low. It was charged at a rate 

 equivalent to from £Tfi to ;,^48 per horse-power per year of 3000 

 working hours. But even the high price did not prevent the 

 use of power so conveniently obtainable. 



Since then a high-pressure water service has been established, 

 the water being pumped by turbines in the Rhone. From this 

 high-pressure service power is supplied more cheaply. On the 

 high-pressure system the cost of the power is about o"]d. per 

 ihorse-power hour, or ;!^8 per horse-power for 3000 working hours. 



In 1889 the annual income from water sold for power pur- 

 poses on the low-pressure system was £20%^ and on the high- 

 pressure system ;^4500. On the high-pressure system the 

 receipts in 1889 were increasing at the rate of ^880 per year. 



In 1889 the motive power distributed, on the high-pressure 

 system alone, amounted to 1,500,000 horse-power hours, there 

 being seventy-nine motors of an aggregate working power of 

 1279 horses. 



In Zurich there is quite a similar system and power, amount- 

 ing to 9,000,000 horse-power hours in the year, distributed hy- 

 draulically to various consumers, who pay a rental of ^1200 per 

 annum. It will be noted that all this power in Geneva and 

 Zurich is obtained from water which has been pumped, and it is 

 the low cost of the water-power which does the pumping which 

 makes this possible. 



But, further, in both Geneva and Zurich the whole of the 

 dynamos supplying electric light are also driven by turbines 

 using pumped water. The convenience of this arises in this way. 

 The fall obtainable in the river in both cases is a small one, and 

 varies. Large turbines are required, and these cannot work at 

 a constant speed. Further, it is expensive to use these large 

 low-pressure turbines to drive directly dynamos which only work 

 with a considerable load for a short portion of the day. The 

 low-pressure turbines in the river are therefore used to pump 

 water to a high-level reservoir, and they work with a constant 

 load all the twenty-four hours. 



From the high-level reservoir water is taken as power is re- 

 quired to drive the dynamos, and the turbines driving the 

 -dynamos are small high-pressure turbines, working always 

 on a constant fall at a regular speed, and easily adjusted by a 

 governor to a varying load. The system seems a roundabout 

 one, but it is perfectly rational, effective, and economical. 



Few persons can have seen Niagara Falls without reflecting 

 on the enormous energy which is there continuously expended, 

 and for any useful purpose wasted. The exceptional constancy 

 of the volume of flow, the invariability of the levels, the depth 

 of the plunge over the escarpment, the solid character of the 

 rocks, all mark Niagara as an ideally perfect water-power sta- 

 tion ; while, on the other hand, the remarkable facilities of 

 transport, both by steam navigation on the lakes and by four 



NO. II 89, VOL. 46] 



systems of railway, afford commercial advantages of the highest 

 importance. From a catchment basin of 240,000 square miles, 

 an area greater than that of France, a volume of water amount- 

 ing to 265,000 cubic feet per second descends from Lake Erie to 

 Lake Ontario, a vertical distance of 326 feet, in 37 J miles. 



Supposing the whole stream could be utilized, it would sup- 

 ply 7,000,000 horse-power. This is more than double the total 

 steam and water-power at present employed in manufacturing 

 industry in the United States. 



Immediately below the Falls the river bends at right angles, 

 and flows through a narrow gorge. The town of Niagara 

 Falls on the American side occupies the table-land in this 

 angle. 



The earliest traders who settled near the Falls erected stream 

 mills in the Upper River in 1725 for preparing timber. Later, 

 the Porter family erected factories on the islands in the rapids 

 above the falls. It was not, however, till about thirty years ago 

 that any systematic attempt was made to utilize part of the 

 water-power of the Falls. Then a canal was constructed from 

 Port Day, about three-quarters of a mile above the Falls, to a 

 fore-bay or head-race along the cliff overlooking the lower river. 

 In 1874 the Cataract Mill was established, taking power from 

 this canal, and other mills were gradually erected till about 

 6000 horse-power were utilized. These mills have been exceed- 

 ingly prosperous, but since the growth of a feeling against the 

 disfigurement of the Falls it has become impossible to extend 

 works of the same kind. 



The idea of a method of utilizing the Falls, capable of greater 

 development, and free from the objections to the hydraulic canal 

 with mills discharging tail water on the face of the cliff, is due 

 to the late Mr. Thomas Evershed, Division Engineer of the 

 New York State Canals. He proposed to construct head-race 

 canals on unoccupied land some two miles above the Falls. 

 From these the water was to fall through vertical turbine pits 

 into tail-race tunnels, converging into a great main tunnel, dis- 

 charging into the lower river. Apart from an inappreciable 

 diminution in the volume of flow over the Falls, this plan avoids 

 any disfigurement of the scenery near the Falls, and permits a 

 head of nearly 200 feet to be made available. It is, however, 

 essential to such a plan that work should be undertaken on a 

 very large scale. In 1886 the Niagara Falls Company was in- 

 corporated, and obtained options over a considerable area of 

 land, extending from Port Day for two miles along the Niagara 

 River. In 1889 the Cataract Construction Company was formed 

 to mature and carry out the constructional works required. 



The present plans contemplate the utilizatioil of 100,000 

 effective horse-power. The principal work of construction is a 

 great tunnel 7260 feet long, which is to form a tail-race to the 

 turbines, starting from lands belonging to the Company, and 

 discharging into the lower river. The tunnel is 19 feet by 21 

 feet, or 386 square feet in area, inside a brickwork lining 16 

 inches thick. 



The base of the tunnel is 205 feet below the sill of the head 

 gate, and permits a fall of 140 to be rendered available at the 

 turbines. The brickwork of the tunnel is lined for 200 feet from 

 the mouth with cast-iron plates. 



The tunnel has been excavated with remarkable rapidity with 

 the aid of drills worked by compressed air. 



The main head-race, about 200 feet wide, will run for about 

 5000 feet parallel with the river, having entrances from the river 

 at both ends. Near the lower reach the Soo Paper Company is 

 already arranging to utilize 6000 horse-power, discharging the 

 water from the turbines through a lateral tunnel into the rnain 

 tunnel. Near this lower reach will also be placed two principal 

 power stations, from which power will be distributed, either 

 electrically or otherwise in ways not yet fully determined. The 

 first turbines to be erected in these power stations will be twin 

 turbines of the outward flow type of 5000 effective horse-power. 

 These turbines have a vertical shaft for driving dynamos or 

 other machinery placed above ground. 



According to Mr. Evershed's original plans, it was intended 

 to distribute water by surface canals to different power users, 

 each of whom would sink his own turbine pits, connected below 

 by lateral tunnels to the main discharge tunnel. Some of the 

 power at Niagara will undoubtedly be used in this way, and in 

 the case of industries requiring a large amount of power it will 

 be economical to purchase a site and water rights. 



Such a plan is, however, not adapted to smaller factories. 

 Obviously for them it would be more economical to develop the 

 power in one or more central stations by turbines of large size 



