66 CANDLES AND LAMPS. 



of unconsumed carbon in the form of smoke, was the cer- 

 tain result. 



The only light for the streets of cities in Europe two or 

 three hundred years ago was furnished by great flaming 

 and smoking torches carried in the hand. The darkness 

 at night, of course, afforded great facilities for the commis- 

 sion of all kinds of crime, and robberies, murders, and as- 

 sassinations increased to such a degree that the govern- 

 ment of Paris at one time organized a guard of armed men 

 to patrol the streets in search of the criminals, lighting their 

 way, of course, by the only kind of illumination they then 

 knew how to produce, viz., that of blazing and smoking 

 torches, which the link-man carried before them in his hand. 



The true remedy for this state of things was to dispel 

 the darkness which occasioned it by devising some way to 

 increase the brightness of the light which could be given 

 by a flame, and then lighting the streets by placing a fixed 

 burner of this increased brightness at every corner. 



The first method of attempting to do this was by means 

 of a reflector placed behind the flame, so as to throw all 

 that part of the sphere of light issuing from the flame, 

 which would naturally go back toward the wall, where it 

 was not wanted, forward into the street. But very soon 

 the attention of scientific men began to be turned to the 

 question whether the intensity of the light itself could not 

 be increased by increasing the intensity of the heat pro- 

 duced, and then promoting the rapidity of the combustion 

 by a more complete and rapid supply of oxygen. There 

 would evidently be a double advantage in this, for, by fur- 

 nishing a full supply of oxygen, all the carbon would be 

 consumed, instead of being allowed in part to escape un- 

 consumed as smoke, and then, moreover, the particles which 

 were consumed would be raised to a higher intensity of 

 heat, and so would become more highly luminous. 



