Maech 9, 1883.] 



KNOWLEDGE 



147 



elapw-d since the Stock Excliange excitement of last 

 snuiiiier. 



The electric light is naturally the chief attraction of the 

 exhibition, but this section can scarcely be regarded as 

 fully representative. Messrs. Siemens have twenty-six of 

 their arc lamps, the dynamo being dri\i'n l)y a Robey engine. 

 The work is performed but indill'ereutly, and as the installa- 

 tion constitutes part of the ordinary lighting arrangements 

 of the building, it can scarcely be looked upon as forming 

 part of the Exhibition. The only other arc lamps of which 

 there is any immediate prospect of being lighted are the 

 well known Pilsen and the Mathiesen, the dynamos for 

 which are to be driven by Hodson's Rotary engines. These 

 engines may be very well in their way, but they are not, 

 in our opinion, calculated to bring much credit to the e.x- 

 hibits. Their speed is far too high, and they are too liable 

 to vary to command our approbation. The Joel lamp 

 tB the only .semi-incandescent light at present vL-^ible, 

 although, in the absence of a catalogue, it is impossible 

 to predict all that will yet be forthcoming. It is 

 to incandescent lamps that the energies of the majority of 

 the exhibitors appears to be directed, although we can see 

 or hear nothing of the Maxim lamp, which .'ihone to such 

 advantage in the north nave of the Crystal Palace last 

 winter. Nor is there any prospect of a display of the 

 Lane-Fox, British, or Fitzgerald lamps. The field is appa- 

 rently in the entire command of the Edison and Swan 

 lamps, and their exhibitors evidently intend doing their 

 best to secure an undivided verdict How far they 

 will succeed, if such be their object, it is difficult to say, 

 4tlkd it is equally difficiilt to conceive anything more pretty 

 «r more chaste than many of the conceptions already, or 

 non to be carried out. 



In a shfcd, at what may be called the north-east corner 

 of the building, is a 2o-horse-power engine, by Davey 

 Paxman, it Co. This is to drive two Edison's dynamos 

 and a Ferranti dynamo. The former are to supply the 

 current necessary for 240 Edison lamps ; and the latter, 

 we are told, for 500 Swan lamps. Owing to a difficulty in 

 the matter of belting, one Edison and the Ferranti are at 

 present running alternately. The Edison requires a speed 

 of 1,200 or 1,300 revolutions per minute, while the Fer- 

 ranti requires 2,000 revolutions to supply the necessary 

 current That this latter speed is highly prejudicial to the 

 mechanical portion of the machine is rendered apparent by 

 tile fact that the present machine is the third tried, the two 

 others having been so much injured as to necessitate their 

 removal. Of course, we must not lose sight of the fact that 

 the machine is a very small one (as will be seen so soon as 

 we can find space to describe it), and, therefore, a high 

 speed does not mean nearly so much as it would in a 

 niaL-hine of any other type used to supply the same 

 number of lamps. The Swan lamps supplied by the 

 Ferranti are used for illuminating the Bath room, fzc, 

 but little is at present to be said of the performance. The 

 Edison lamps, of which there are at present about a 

 hundred in use, are illuminating a suite of apart- 

 ments in the Western Gallery. Doubtless, the 

 most attractive portion of this display is the " Grotto," 

 which is exceedingly pretty, and shows to what a 

 state of perfection the incandescent lamp can attain 

 m response to the artistic requirements of the age. 

 Close to this exhibit is a display by Messrs. Edmundson it 

 Co., agents for the Swan Company. They have already 

 163 Uuips arranged in a multiplicity of most cunning de- 

 vices. Part of the exhibit takes the form of an elegantly- 

 appointed drawing-room, to the decorvation of which the 

 Swan lamp lends itself very considerably. Pendant from 

 the centre of the ceiling is a bright brass chandelier sup- 



porting fifteen lamps, each of which is encased in a rose- 

 tinted ghiss liood. The cllect of the light shining through 

 these on to the brass work is very striking. Outside the 

 room is another brass chandelier, very beautiful in design, 

 which is intended to carry forty lamps. When every- 

 thing is complete, this exhibit will be interesting to the 

 last degree. There are to be in all 250 lamps. A Siemens' 

 dynamo is in use, and is driven by a 2,")-h.p. engine of Messrs. 

 Davey Paxman, it Co.'s, fitted up in a temporary shed 

 attached to the north-west corner of the building. The 

 difficulties surmounted by the representative of these tirst- 

 class engineers may be almost described as Ilerculean, 

 and great credit is due to him for having so satisfactorily 

 and so fully achieved his task. In the same shed he has 

 fitted another engine — one of the firm's thirty-horse-power 

 single cylinder engines, havinc; two separate boilers to 

 supply the requisite steam. The two engines drive on 

 the same shaft, which, when the electricians are ready, 

 will supply the motive-power for working the dynamos 

 required for Messrs. Edmundson it Co.'s Swan Lamp 

 exhibit and a number of Jablochkofl' lamps. Messrs. 

 Patterson it Cooper will also exhibit the recently-intro- 

 duced Elphinstone and Vincent Dynamo, and another 

 patented by Messrs. Levey it Lumley. 



There are good displays of pneumatic and electric bells, 

 the liest being that of the Signal Engineering Company. 

 The only other feature we can now refer to is the 

 " Secondary Generator," patented by Messrs. Gaulard it 

 Gibbs. In this apparatus it is intended to convert a 

 current of a given pressure, or electro-motive force, into 

 other currents of any desired electro-motive force. This is 

 accomplished on the principle of the Ruhmkorff coil. The 

 original currents traverse a primary coil, and, in so doing, 

 induce currents in a numVier of enveloping coils. If these 

 latter coils are joined in " series," a high-tension current is 

 derived, while joining them in parallel circuit causes a low- 

 tension current to be developed. It is claimed that this 

 apparatus will revolutionise and render practical in every 

 sense of the word the application of electricity to domestic 

 and commercial purposes. Time will prove how far the 

 anticipations of the inventors will be realised, but wo will 

 refer more fully to the exhibit in our next notice. 



It is to be earnestly hoped that intending exhibitors will 

 now hamper the directors as little as possible, and do their 

 best to make the exhibition a success. 



THE GREAT COMET OF 1882.— II.* 



By Professor C. A. Young. 



TTTIIEX the writer first saw the comet, on September 

 VV 19, it was impossible, with the great twenty three- 

 inch equatorial, to make out much except the nucleus 

 itself. The comet was so near the sun that the object- 

 glass could not be screened from the direct sunshine, which 

 filled the whole field with glaring light The finder of the 

 instrument is itself, however, a powerful telescope of five 

 inches aperture, and this was perfectly screened by the 

 great tube, so that it furnished an admirable view of the 

 beautiful object. To the naked eye the comet looked like 

 some white-winp'ed bird in swift flight towards the sun. 

 The telescope showed the wings to be long, curved 

 streams flowing backward from each side of the head — 

 backward, that is, with reference to the sun ; but they were, 

 of course, really in advance of the comet, which at this time 

 was receding from the sun. The head of the comet had for 

 its centre a small round and brilliant nucleus, not well 



• From the Popular Science Monthly. 



