VOLTAIC ARC LAMPS. 153 



The first automatic electric lamp appears to have been in- 

 vented in 1845 by Thomas Wright; but it was not until 

 1848, when Stake and Petrie, in England, and Foucault, in 

 France, invented their regulators that attention was attracted 

 to the matter ; and before these apparatus could be regarded 

 as capable of any practical application, Archereau on the one 

 hand, and J. Duboscq on the other, had used them for 

 numerous experiments in projection. From that time, and 

 especially after the curious results obtained by the machines 

 of the Alliance Company, people began everywhere to apply* 

 themselves to the improvement of these apparatus, and a 

 multitude of systems were invented, the most important being 

 those of Serrin, Duboscq, Siemens, Carre, Lontin, Rapieff, 

 Brush, &c. Having in the 5th vol. of my Expose des appli- 

 cations de relectricite described most of these numerous 

 systems, I shall here concern myself only with those that 

 have become common in practice. 



Regulators of the electric light may be divided into six 

 classes, viz. : i. regulators founded on the attraction of sole- 

 noids, and to this class belong the regulators of Archereau, 

 Loiseau, Gaiffe, Jaspar, Carre', and Brush; 2. regulators 

 founded on the approximation of the carbons by successive 

 movements produced electro-magnetically ? and among these 

 we may mention the regulators of Foucault, Duboscq, 

 Deleuil, Serrin, Siemens, Girouard, Lontin, Mersanne, 

 Wallace Farmer, Rapieff; 3. regulators with circular car- 

 bons, the most important types being the regulators of 

 Thomas Wright, Lemolt, Harisson, and Reynier; 4. regu- 

 lators with a hydrostatic action, amongst which we may name 

 those of Lacassagne and Thiers, Pascal, Marcais and Du- 

 boscq, Way, Molera, and Cebrian; 5. reaction regulators, 

 such as those of Fernet, Van Malderen, and Bailhache; 

 6. electric candles on the Jablochkoff plan, and others. 

 The incandescent carbon regulators forming a class by them- 

 selves, we shall discuss farther on. 



Of all these apparatus, those of Foucault and Duboscq, 



