Abstract
II. THE second district of the City which has been illuminated by electricity is that embracing Black-friars Bridge, upon which there are seven lamps. Bridge Street, in which there are four lamps, Ludgate Circus taking three lamps; Ludgate Hill four lamps; north side of St. Paul's six lamps. and Cheapside, as far as King Street, eight lamps. thirty-two lamps in all, replacing 150 gas lamps; and moreover, all these lamps are fixed upon one circuit, which is operated practically by only one machine, and that fixed more than a mile away, at the manufactory of the Brush Company in York Road, Lambeth. The total length of this circuit is over 20,000 feet. It consists of a copper cable made up of seven best copper wires surrounded with a thick layer of gutta-percha protected externally with tape that has been well tarred. This wire gives a total resistance of 7.5 ohms., and is protected by iron pipes like the Siemens method, and laid on the principle so well known in telegraphy. The dynamo-machine is of the familiar Brush form, and at present there are two machines of the size known as No. 7 cabled up in series, but forming practically only one machine. These two machines are intended to be replaced by one dynamo-machine, which, at a velocity of 800 revolutions, and worked by 32 indicated horse-power, will maintain forty lamps burning. The main feature of the Brush system is its simplicity, one machine working a number of lights, and those who visit the engine-room of Messrs. Siemens, and then that of the Brush Company, cannot help being struck by the immense difference in the contrast between the two. In Siemens' engine-room one feels in the midst of a whirling cotton manufactory. at the Brush works one sees nothing but a single engine working a single machine quietly and without fuss or flurry.
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Electric Lighting 1 . Nature 24, 33–35 (1881). https://doi.org/10.1038/024033a0
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DOI: https://doi.org/10.1038/024033a0