May 12, 1881] 



NATURE 



33 



we breakfasted with them in one of the most picturesque 

 spots imaginable, and finally how we realised with diffi- 

 culty that we were only four days' journey from London, 

 ■while breakfasting, under a bower of carouba branches, 

 off sheep roasted whole over hot ashes placed in holes in 

 the earth, manipulated with hunting-knives and without 

 forks, flat circular cakes of Kabyle bread serving us for 

 plates, and gigantic wooden bowls of kous-kous as a 

 second course. 



The amicable attitude of these once savage aborigines 

 seemed to us to re-echo the key-note of the Algiers meet- 

 ing of the French Association ; to proclaim loudly and 

 with no uncertain sound that the " conquete pacifique de 

 I'Afrique septentrionale par les Frangais " has indeed 

 become an accomplished fact. G. F. Rodwell 



ELECTRIC LIGHTING' 

 II. 



THE second district of the City which has bsen 

 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 si.x 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 fi.xed more than a mile away, at the 

 manufactory of the Brush Company in York Road, Lam- 

 beth. 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 v?ith 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 dilTerence 

 in the contrast between the two. In Siemens' engine- 

 room one feels in the midst of a whirling cotton manu- 

 factory ; at the Brush works one sees nothing but a 

 single engine working a single machine quietly ani with- 

 out fuss or flurry. 



At present a Galloway engine is used by the Brush 

 Compan\', but when the large 40-Iight dynamo-machine 

 is set to work a Brotherhood 3-cylinder engine of 32-horse 

 power will be used. These engines are admirably adapted 

 for electric light purposes ; they are bolted on to the same 

 frame as the dynamo-machine, and give a compactness 

 and solidity to the whole that is very striking. 



The Brush lamps differ but very little from the gene- 

 rality of arc lamps. The carbons are maintained apart 

 by what is known as a "sucking" coil; and the hi up 

 possesses one or two very ingenious designs to shunt it out 

 of circuit when anything fails and to shunt it in when all 

 is in order. It is a kind of duplex lamp, supplied with a 

 double set of carbons, each of which burns for eight 

 hours, the total illuminating durability of the lamp being 

 therefore sixteen hours. These lamps are fixed upon the 

 ordinary lamp-posts, which have been raised 22 feet 

 higher than usual, so as to maintain the lamp 16 feet 

 from the ground. They are surmounted by very ugly 



* Continued from p. 7. 



roofs that are neither covers nor reflectors, and the mode 

 in which these lamp-posts have been utilised is the least 

 commendable feature of this system. Indeed the Com- 

 pany might have made much more of their facilities. Com- 

 pared with the tall posts in the remainder of Cheapside 

 they make an unfavourable impression. The globes that 

 embrace the light are too small, and the Company itself 

 seems not to have arrived at the proper decision as to the 

 best quality of globe to use, for in some places the lamps 

 have clear globes, in others ground-glass, and in others 

 opal globes, made, we believe, by Mr. Frederick Siemens 

 of Dresden. 



It cannot be said that the mode of illumination adopted 

 by the Brush Company is perfect at present. The theory 

 of the proper distribution of the light has been neglected. 

 The lamps are scattered about in an irregular manner 

 that is quite offensive to the eye, and though the effect of 

 each lamp is certainly brilliant, the effect of the whole is 

 rather displeasing. It is very wonderful that so much 

 light should be produced from a point so far, and there is 

 no doubt that the public mind has been captivated by the 

 brilliancy of the lamps. The scientific eye however sees 

 room for improvement, and it is hoped for the sake of the 

 success of the experiment that the Brush Company will be 

 guided by the experience of disinterested persons. The great 

 merit of their system is the simplicity of the machinery 

 employed, as well as the brilliancy of the light, but occa- 

 sionally the lights are subject to great want of steadiness, 

 and it is much feared, with the quality of the cable they 

 have used and the enormous electromotive force, that the 

 usual faults accompanying underground wires will develop 

 themselves rather largely. In fact, two very serious breaks- 

 down have already occurred, and they are about to replace 

 their conductor by a better one. They will have to pay 

 dearly for their neglect of common experience. 



So far the experiment has shown that the practical 

 lighting of streets by electricity is not only feasible but 

 practicable. Moonlight has certainly been thrown into the 

 shade, for the streets of the City are better illuminated 

 by electricity than by fair Luna. It is quite possible to 

 read a letter or to see one's watch at any point in King 

 William Street. Indeed the smallest object can be seen 

 anywhere, even in the middle of the road. Running-over 

 has been rendered impossible. 



The outside districts not specially favoured are clam- 

 mering for electric lighting, but much has yet to be learnt 

 before the experiment can be determined as final. For 

 instance, we have the Lontin system to be tried, and we 

 should certainly like to see that most energetic and suc- 

 cessful engineer, Mr. Cromplon, test his system in the 

 London streets. Incandescent lamps are looking up and 

 deserve a trial. 



The best mode of distributing light has not yet been 

 settled. 



It would seem that a compromise between the central- 

 ised system of Siemens and the distributed system of the 

 Brush Company is that needed to solve the problem of 

 proper street illumination. But instead of carrying- 

 lamps irregularly down streets on hideous lamp-posts it 

 would almost seem that the ancient defunct mode of 

 swinging limps across streets from housetops would be a 

 better mode of illuminating streets. Take, for instance. 

 Regent Street. If that street had suspended above it, at 

 the height of 40 feet or 50 feet and at about every 100 

 yards, a Brush lamp fitted on the top of a graceful iron 

 arch, or suspended on wire ropes between the tops of the 

 houses, nothing could possibly be greater than the effect. 

 Light arches thrown across the street might even be a 

 convenient mode of suspending the wires forming the 

 circuits, for overhead wires have a considerable advan- 

 tage over underground wires in this, that they cool more 

 rapidly and allow more electricity in consequence to pass 

 through. More than that, they require no insulation, and 

 the monev thrown into their insulation could be thrown 



