Notes

Abstract

PROF. GEORGE FORBES, F.R.S., who has for the last three years been engaged on the utilisation of Niagara Falls, has, we understand, just returned to this country from the United States, the construction stage of the work being now completed. The close of the three years of Prof. Forbes's connection with the great work at Niagara Falls, which marks the change from the period of design and construction to the period of commercial activity in the existence of the Niagara Falls Power Company, forms a fitting opportunity for expressing the sense of gratification that all Englishmen, and the scientific world in particular, must feel in having had one of their evolved a system which for completeness, adaptability, and security against breakdowns, had not been dreamt of before. The adoption of the alternating current before its value was fully realised by others, the initiation of the world in the use of a lower frequency than any that has hitherto been employed, and the remarkable confirmation of the foresight as to the economy of large transformers at high electric pressure, even at the low frequency employed, that has been established, are matters for congratulation. Although for fuller particulars of the system and apparatus employed, we must refer our readers to a previous account (NATURE, vol. xlix. p. 482), we may draw attention to the method by which Prof. Forbes met one of the most troublesome questions in connection with the design of countrymen chosen to undertake the important and difficult duties of electrical consulting engineer to an undertaking of such magnitude. The manner in which those duties have been discharged, and the pioneer services which Prof. Forbes has rendered them in respect of the work, have, we are in a position to say, received most gratifying testimony and cordial acknowledgment from his Company, who recognise in Prof. Forbes the scientific attainment, combined with independence of thought and action, which have been invaluable throughout the stage of operations now completed. Few realise the many novel conditions that have had to be met at Niagara Falls. But by dint of years of study of the many problems presented, Prof. Forbes has the 5000-horse power generators (Fig. 1), arising in consequence of some requirements of the turbine designers—viz. the securing of a certain necessary momentum of the revolving part of the dynamo, without increasing the weight to be supported by the hydraulic piston in the turbine above a certain limit. The difficulty was met by fixing the armature, and revolving the field-magnet, formed of a nickel-steel ring with the pole-pieces pointing radially inwards, outside, the ring, or yoke, and the pole-pieces being supported by a bell-shaped cover fixed rigidly to the top of the vertical shaft from the turbine, the shaft being supported by bearings in the interior of the fixed armature. The foreseen ability to convert the alternating current into continuous current, and the low frequency into high frequency, which is now realised in the invention of Messrs. Hutin and Leblanc, gives greater elasticity to the system; while the precautions taken to avoid sudden opening or closing of the circuits, gives a security against troubles experienced in the past by others such as has not obtained before. The success that has attended Prof. Forbes's efforts during the period of design and construction is of good augury for a successful issue to the commercial stage which the Niagara Falls Power Company now enters upon.