72 



THAT'S IT; 



though furnished with glass, 

 gave a very feeble light ; jet they 

 continued to be employed in the 

 principal cities, from about the 

 year 1730 to 1813-25. In 

 country places, and on the sea- 

 coasts, beacons, 18, were lighted 



309. 



in the most dangerous places, to 

 guide the mariner or the way- 

 farer. They were also set up 

 by baronial halls and mansions, 

 to direct those who had ridden 

 forth in the day, on their home- 

 ward journey. But the light 

 which they afforded was uncer- 

 tain and insufficient. 



310. 



311. 



ployed, the simplest of them 

 being formed of cross-pieces of 

 wood, the better ones of metal 

 ornamented. Draughts of air 

 made the candles nicker, and the 

 frequent necessity for snuffing 

 them was a great inconvenience. 

 To obviate the annoyance of 

 draughts, glass shades, 1, 2, of 



For public assemblies, candle- 

 clutu dehors, 19, 20, were em- 



312. 



313. 



various forms, were adopted. But 

 still these contrivances afforded 

 very feeble illumination. Large 

 wicks had been tried, then a 

 number of small wicks, side by 

 side, then a thin line of wick ; but 

 none of them were satisfactory, 

 and it was not until 1785 that 

 any material improvement was 

 made. M. Argand, of Greneva, 

 having found that the light of a 

 lamp depended upon the perfec- 

 tion of combustion, and that the 

 latter was promoted by a plenti- 

 ful supply of atmospheric air, 

 invented the circular wick, 3, by 

 which a current of air 

 was obtained, not only 

 on the outside of the 

 flame, but in its centre 

 also. The heat caused 

 by the burning of the 

 wick, 4, induced air to 

 rush in, 5, and, passing 

 upwards to the flame, 

 it increased the inten- 

 sity of the light. Still, the effect 



