Figure lo. — Archereau's arc-light regulator. 

 The downward weight of the lower carbon 

 was balanced by the upward pull of the 

 solenoid core. From T. du Moncel, Expose 

 des applications de I" electricite, Paris, ed. 2, 

 1856-1862, vol. 3, pi. 4, fig. 3. 



Figure 1 1 . — Duboscq's version of the Foucault 

 arc -light regulator. The rate of ascension of 

 the lower carbon was controlled by a clock- 

 work whose escapement was controlled by 

 the solenoid (E). From T. du Moncel, 

 Expose des applications de P electric; te, Paris, ed. 

 2, 1856-1862, vol. 3, pi. 4, fig. 4. 



several arc lights in the same circuit, the former in 

 1849 and the latter in 1855. However, such a circuit 

 could be maintained only for a short time.'^ After 

 considerable study, L. F. Wartmann, of Switzerland, 

 asserted that the electric light could i^e subdivided but 

 that the method depended on the system used in the 

 distribution of the illumination.''' 



However, until the end of the 1870's, all regulators 

 were inherently unstable when placed in the same 

 circuit, except pos.sibly one. When placed in series, 

 if one went out, they all went out; and when placed 

 in parallel, one tended to quench the others. The 

 only kind of regulator that did not have this innate 

 defect was that of Lacassagne and Thiers, but it is 

 difficult to determine to what extent this advantage 



16 Cosmos, 1855, vol. 7, pp. 703-704; 1856, vol. 8, pp. 30-32. 



'" L. F. Wartmann, "Sur TEclairage electrique," Bibliotheque 

 Universelle de Geneve, Archives des sciences physiques el rwturelles, 

 1857, vol. 36, pp. 323-334. 



was realized in practice by the inventors.'* At any 

 rate, the consensus was that it was not possible to 

 subdivide the electric light. 



In the decade between 1855 and 1865 a number 

 of attempts were made to use the arc light for military 

 operations and for public celebrations. It has been 

 said that the arc light was tried during the naval 

 attack on Kinburn in 1855 during the Crimean 

 War, and in 1859 during the Italian war of independ- 

 ence. Joseph Henry devised an arc light in 1863 

 that was intended to be used for the siege of Charles- 

 town during the Civil War, and in the same year 

 Boston celebrated Union victories by arc-light 

 illumination. On the occa.sion of the visit of Queen 

 Isabella II of Spain to Paris in 1864, Napoleon used 

 11 Serrin regulators to illuminate the fountains of 



19 Du Moncel, op. cit. (footnote 5), vol. 3, pp. 250-251. 



342 



BULLETIN 228: CONTRIBUTIONS FROM THE MUSEUM OF HISTORY AND TECHNOLOGY 



