74 ELECTRIC LIGHTING. 



In order that the arrangement might utilize the more 

 powerful effects of the electro-magnet when it acts like a 

 horseshoe magnet, and that the inducing force might not be 

 divided, the t\vo armatures were arranged in such a manner 

 that when the iron parts of the bobbin a were opposite the 

 polar armatures, the same parts of the bobbin d were in a 

 perpendicular position, and therefore in that position in which, 

 leaving the polar armatures which had acted on them, the 

 direct induced currents were produced. 



Of course the two bobbins were set in motion by two 

 belts passing over the same drum. 



With the machine of the small dimensions, shown at the 

 Exhibition of 1867, the current transmitted externally was 

 equivalent to that from 25 or 30 Bunsen cells. It was able 

 as we have already stated, to supply somewhat discon- 

 tinuously, it is true one of Foucault's medium-sized electric 

 light regulators. 



Gramme's Machine. The Gramme machine, of which 

 so much has lately been heard, and which has produced the 

 most remarkable results, was originally contrived, so far at least 

 as its general arrangement goes, by Paccinotti, of Pisa, and 

 Worms, of Romilly, as is proved by a description published 

 by the former in the Nuovo Cimento for 1860, and by a patent 

 taken out by the latter gentleman on the 3rd March, 1866.* 



It was, in fact, only in 1870 that the Gramme machine 

 was constructed ; but the principle of the combination of 

 currents in this machine was quite different from that em- 

 ployed in the two which preceded it, and it is for this reason 

 that the one has given unlooked-for results, while the others 

 have remained in the state of ordinary machines. We shall 

 here, therefore, concern ourselves with only the Gramme 

 machine, which is besides the best known at the present day 

 of all dynamo-electric machines. 



* See the description of this machine in my Expose des applications de 

 I'ttectricite, t. II., p. 222. 



