LIGHT AND ITS ARTIFICIAL PRODUCTION. 275 



the exact time that a spark was first kindled by man is of no impor- 

 tance here. We might rather be interested in the manner in which it 

 was accomplished. Did fire in the shape of a meteor fall from heaven, 

 was its terrible force first manifested in the glowing lava of the vol- 

 cano, or are we indebted for it to the hard labor of man in his struggle 

 with nature for existence? 



The most natural and most probable explanation is that man learned 

 to i)roduce a spark at will while engaged in making the first weapons 

 of stone. Fire was certainly discovered independently in numerous 

 parts of the earth. 



The significance of this first acquaintance of man with fire for the 

 development of higher civilization can not be overestimated. It is 

 reflected in the mythology and songs of all lands. Greek mythology 

 elevates the fire bringer to the dispenser of light in a spiritual sense, 

 while the Eomans worshiped Vesta as the goddess of the hearth and 

 also of the sacrificial fires, and in honor of the birth of light the eternal 

 fire was guarded by the vestal virgins. 



It is a great leap from the hearth fire and the sacrificial fire to the 

 incandescent electric light and incandescent gaslight. For a long time 

 the fire on the hearth served at the same time as a source of light, a 

 custom preserved to this day in many German spinning rooms, and 

 among the Eskimo no other light is known. First came the flickering 

 kindling-wood pan, then the resin and pitch fagots, then reeds covered 

 with wax, j)ointing to the impending important separation of light and 

 fire, which was nearly accomplished in the lamp of the ancients and the 

 taper of the middle ages. The principal aim to-day of artificial illumi- 

 nation is this separation of light and heat, an end we are gradually 

 attaining, even though the time may still be distant when light will be 

 produced, at least for common use, without attendant heat effect. 



The candle owed its origin to the development of chemical technology 

 in the early part of this century, by which solid fats, burning excel- 

 lently, are made from cheap raw materials, and by which new sub- 

 stances, such as parafiine, are separated from coal tar. Neither was 

 the oil lamp of the ancients neglected. The introduction of the hollow 

 wick by Count Argand in 1786 and of the chimney by the apothecary 

 Quinquet, of Paris, in 1765 were specially important, even if the sub- 

 stitution of petroleum for rape seed and olive oil was necessary to 

 increase its efficiency to what it is to-day. 



Gas lamps mark the transition to illuminating gas. In these the very 

 volatile products of the dry distillation of tar, e. g., ligroin, benzine, 

 petroleum, ether, etc., are first vaporized, and the resulting vapor is 

 burned. Hydrogen gas passed through petroleum gives an excellent 

 illuminating gas. 



The ordinary illuminating gas, which was utilized in England as early 

 as 1792, was not introduced into Germany until more than thirty years 

 later. It was formed by heating bituminous coal in retorts to a red 

 heat in the absence of air. The escaping gases, after being thoroughly 



