464 FRAGMENTS OF SCIENCE 



Through the liberality of the proprietors of the 

 "Times," every facility has been given to M. Rapieff to 

 develop and simplify his invention at Printing House 

 Square. The illumination of the press-room, which I 

 had the pleasure of witnessing, under the guidance of 

 M. Rapieff himself, is extremely effectual and agreeable 

 to the eye. There are, I believe, five lamps in the 

 same circuit, and the regulators are so devised that 

 the extinction of any lamp does not compromise the 

 action of the others. M. Rapieff has lately improved his 

 regulator. 



Many other inventors might here be named, and fresh 

 ones are daily crowding in. Mr. Werdermann has been 

 long known in connection with this subject. Employing 

 as negative carbon a disk, and as positive carbon a rod, 

 he has, I am assured, obtained very satisfactory results. 

 The small resistances brought into play by his minute arcs 

 enable Mr. Werdermann to introduce a number of lamps 

 into a circuit traversed by a current of only moderate 

 electro-motive power. M. Eeynier is also the inventor of 

 a very beautiful little lamp, in which the point of a thin 

 carbon rod, properly adjusted, is caused to touch the cir- 

 cumference of a carbon wheel which rotates underneath 

 the point. The light is developed at the place of contact 

 of rod and wheel. One of the last steps, though I am in- 

 formed not quite the last, in the improvement of regula- 

 tors is this: The positive carbon wastes more profusely 

 than the negative, and this is alleged to be due to the 

 greater heat of the former. It occurred to Mr. William 

 Siemens to chill the negative artificially, with the view 

 of diminishing or wholly preventing its waste. This he 

 accomplishes by making the negative pole a hollow cone 



