TIMTEBZ 



Figure 7. — How a French cartoonist imagined 

 the lodger of the future would be given his 

 electric "candle" by the concierge. From 

 V Illustration, September 30, 1848, vol. 12, 

 p. 69. 



time, and so other means of regulating the carbons 

 were sought. Joseph Lacassagne and Rodolphe 

 Thiers devised a difTerential arc light regulator in 

 which the current resulting from the difference of 

 two controlling circuits fed the moving carbon at 

 the proper speed (figs. 14, 15). By u.sing a battery 

 of 60 Bunsen cells, Lacassagne and Thiers successfully 

 illuminated a square in their home city of Lyons in 

 1855, and the following year they lit up the Arc de 

 I'Etoile and the Avenue des Champs Elysees for four 

 hours in a vain attempt to interest Napoleon III in 

 their invention. After successful trials at Lyons 

 again, where they used two lamps to light the Rue 

 Imperiale during the evenings for the entire month 

 of March 1857, Lacassagne died; in the same year 

 the Societe d'Encouragement pour ITndustrie 

 Nationale awarded a bronze medal for the Lacassagne 

 and Thiers regulator. Thiers sought to exploit the 



Figure 8. — Demonstration of the new electric light at a balloon 

 ascension at The Vauxhall in London. From Illustrated 

 London News, August 25, 1849, vol. 15, p. 144. 



340 



BULLETIN 228: CONTRIBUTIONS FROM THE MUSEUM OF HISTORY AND TECHNOLOGY 



