678 FRAGMENTS OF SCIENCM. 
of the latter. In the de Meritens machine the commu- 
tator is abolished. The internal heat is hardly sensible, 
and the absorption of power, in relation to the effects 
produced, is small. With his larger machines M. de 
Meritens maintains a considerable number of lights in the 
same circuit. * 
In relation to this subject, inventors fall into two classes, 
the contrivers of regulators and the constructors of 
machines. M. Rapieff has hitherto belonged to inventors 
of the first class, but I have reason to know that lie is 
engaged on a machine which, when complete, will place 
him in the other class also. Instead of two single carbon 
rods, M. Rapieff employs two pairs of rods, each pair 
forming a V. The light is produced at the common junc- 
tion of the four carbons. The device for regulating the 
light is of the simplest character. At the bottom of the 
stand which supports the carbons are two small electro- 
magnets. One of them, when the current passes, draws 
the carbons together, and in so doing throws itself out of 
circuit,leaving the control of the light to the other. The 
carbons are caused to approach each other by a descending 
weight, which acts in conjunction with the electro-magnet. 
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 disc, 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 
*The small machine transforms one-and-a-quarter horse-power 
into heat and light, yielding about 1,900 candles; the large machine 
transforms five-horse power, yielding about 9,000 candles. 
