60 On Recent Improvements in Electric Lighting. 



supplying a number of Andree incandescent lamps. On in- 

 quiry we found that, although the lights were intense they 

 were unsteady, but that when the whole current was directed 

 into a large Crompton lamp it was all that could be desired. 

 The Gramme machine was driven by a Wheelan engine of five 

 horse-power, with a very small fly-wheel and a governor 

 that did not work. We were informed that the engine 

 ran so steadily that this latter circumstance did not inter- 

 fere with it ; but assuming that the Andree system has been 

 perfect in other places, it would not be difficult to account for 

 any irregularity in the present instance, for with several in- 

 candescent lamps in circuit, each giving only a comparatively 

 small light, I can imagine that the slightest variation in the 

 driving power would make itself very apparent in such 

 lamps, although when the current was utilised in a single 

 arc light of large size its fluctuations were not, perhaps, 

 discernible. 



Professor Tyndall recently stated that " he did not believe 

 any fresh discovery needed to make the electric light of 

 general application for all large places ; " while Sir William 

 Thompson stated that " he believed before long it would be 

 used in every case where a fixed light was required ; that 

 there was immense progress in the actual work carried out 

 by the practical men of the day." Sir William Armstrong 

 nas an electric lamp in his library, the Dynamo machine 

 being some mile and a-half distant, and driven by a turbine 

 wheel from a large fall of water. 



The British Museum is lighted on Siemens' principle by 

 means of four lights of 5000-candle power each, produced 

 by continuous current, and seven lamps of 400-candle power 

 each, supplied by an alternate current machine ; another 

 Dynamo machine serves to excite all the electro-magnets. 

 The four single lamps are on the pendulum principle ; the 

 other seven are differential, and the lights are maintained 

 for six hours without touching the lamps. The machines are 

 driven by two eight horse-power steam engines, about 200 

 yards away from the reading-room. Last winter, about ten in 

 the morning, a dense fog arose, and the many visitors in the 

 museum prepared to take their departure, not being able to 

 read longer, when, the authorities being equal to the occa- 

 sion, the electric light was turned on, and kept so during the 

 whole day, to the great satisfaction of the readers. The 

 lamps in the library are fitted with gilt reflectors, and they 

 are stated to be an improvement on the silvered. 



