328 SEC. 10. ELECTRICITY. 



resistance. This resistance diminishes with the weakening of the principal 

 current, and the consequent increase of the auxiliary current compensates 

 that weakening. 



14O4a. Regulator, by Foucault. M. J. Duboscq, Paris. 



1405. Apparatus to make the Electric Light, derived 

 from a Voltaic Battery, constant in its position and intensity. 



Elie Wartmann, Professor of Natural Philosophy in the 

 University of Geneva. 



This apparatus, called fixateur for the electric light, was used in the years 

 1856 and 1857 for lighting the harbour of Geneva. A full description is to 

 be found in the " Archives des Sciences physiques ct naturelles," December 

 1857. By means of an electro-magnet and of gravity, two points of carbon 

 are placed and kept at such a distance that the light produced by the current 

 of an electric battery may be as bright as possible. 



14O6b. Regulator of Electric Light, by Serrin, with glass 

 globe. M. Breguet, Paris. 



1406. Regulator of Electric Currents, after the plan of 

 M. Mascart. M. Redier. 



1407. Regulator for the Electric Light. M. Carre. 



1408. Artificial Charcoal Sticks for the Electric Light. 



M. Carre. 



1409. Electric Lamps, 1 small and 1 large. These lamps 

 are automatic in their motion ; in them the carbon points are caused 

 to approach or recede from each other. 



Siemens and Halske, Berlin. 



14O9. Electric Lamps. These lamps are automatic in their 

 action, in them the carbon points are caused to approach or recede 

 from each other as required, without the aid of clockwork. 



Siemens and Halske, Berlin. 



VIII. APPARATUS FOR DETECTING AND MEASUR- 

 ING DIFFERENCES OF ELECTRIC POTENTIAL 

 AND CURRENTS OF ELECTRICITY. 



a. ELECTROSCOPES AND ELECTROMETERS. 



1410. Two Repulsion Electrometers constructed and 

 used by Van Maruin. Teyler Foundation, Haarlem. 



1411. Small Pocket Electroscope used by H. B. de 

 Saussure during his excursions in the Alps. 



M. H. Henri de Saussure, Geneva. 



