THE ELECTRIC LIGHT.

Thames Star, Volume X, Issue 3123, 20 February 1879, Page 1

THE ELECTRIC LIGHT.

At the usual fveekly meeting of the Society of Arts, held on Wednesday, Or C. W. Siemens, F.R.S., in the chair, a paper on electric lighting was read by Mr J. N. Shoolbred, M. Inst. C.E. The object of the author was to present some results of the application of electric lighting to industrial purposes, especially ai regards cost. He noticed first the Holmes and the Alliance magneto-electric machines, giving alternating currents and single lights for lighthouse use. Secondly, he referred to the dynamo-electric ma* chines, producing single lights for general industrial purposes, as well as for light' houses, and including the Siemens and the Gramme machines. In his third group the author included the machines used for producing divided lights, each group indicating a marked period representing a clearly defined stage of progress in electric lighting. With regard to co%t, Mr Sboolbred s! ated tbatin every instance his figures and particulars were- those afforded by the users of the various lights ancf not by the inventors or their representaives. In the case of the Holmes machine the annual cost per lighthouse was about £1,035, inclusive of interest, repairs and wages. With the Siemens machine the annual cost was about £494 per lighthouse, including the interest and' the other expenses. .With the Alliance machine as used at Havre, the cost was about £474 per annum per lighthouse, interest, &c, included. The single-light Gramme machine has been in ute in the Paris goods station of the Northern of Prance Eailway for two years. Six machines have been kept going with one light each, and the cost is found to be 5d per light per hour, or with interest on outlay at 10 per cent., 8d per hour. The same light at the ironworks of Messrs .Powell, at Rouen, was stated to cost 4d per light per hour, exclußive of interest and charge for motive power, the latter being derived from one of the engines on the works. In 1877 a series of experiments were carried out with the Lontin light at the Pars terminus of the Paris, Lyons, and Mediterranean Eailway. The passenger station was lighted; and the results were so satisfactory that the company have entered into a permanent contract with the proprietors of the Lontin light for lighting their Paris goods station with 12 lights, at a cost of 6d per light per hour. The Western of France Railway Company have had six Lontin lights in the goods station at the Parit terminus, St. Lazare, since May last, and 12 lights in the passenger station since June. Careful experiments have shown the Cost to be 8d per light per hour, inclusive' of interest. Referring to the Jablochkbff light, Mr Shoolbred placed before the meeting some particulars with regard to its application in the Avenue de FOpera, Paris, which were afforded him by M. J. AUard,. the chief engineer of the lighting department of the City -of Paris; It _appears rtbat the authorities pay the Socie'tie' G4ue*rale d'Electricit<s 37K. 2c. per hour; for the 62 lamps in use there. These 62 lamps supersede 344 gas jets which were previously used, and. which cost the authorities 7 214f. per hour. The electric illumination, however, is considered as equal to 682 gas-jets, or about double the original illumination—that is, to ■ cost of 1445f. per hour as against 372f. for the electric light, the cost of which, therefore, is 2 6 times that of the gas. The eon* tract for lighting by electricity was terminated by the City of Paris on the 30th uU, and the authorities have declined to renew it except at the price paid for gas —namely, 7'224f. (or about 6s) per hour, and that only until the 15th of January next. These terms have been accepted by the .Socie'te', so that the price paid to them will be at the rate of about l£d per light per hour. Mr Shoolbred stated that the SocLe'te' place their expenses at,.l'o6f. ( o v just lid) per light per hour, which, however, they hope to reduce.by one-half. A se/ieV of careful photometric experiments carried out by the municipal authorities with the Jablocbkoff lights, above referred to, showed each naked light to posses? & maximum of 300 candles of iofcens'ty. Wii.V the glass plobe this wa« reduced to 180"candles, showing a loss of 40 per cent., wM'« during the darker periods through whu"h the light! passed the light was as low as 90 candle?, The foregoing w«re the only authenticated particulars which the Author eovild obtain as regards the working of tbe various electric systems of electric lighting. In conclusion Mr Shoolbred referred to the Eapieff light at The Times office which, he observed, worked fairly and with regularity, which could not be said of all others, and it might therefore be entitled to take rank as an established application of electric illumination. The paper was illustrated by the Siemens, Eapieff, Serrin, and other forms of electric light, which were sliown-in operation.