OR, PLAIN TEACHING. 



73 



was insufficient; the cold air 

 which surrounded the flame on 

 its outside, interfered with the 

 completeness of the combustion, 

 or burning, the wick became 

 loaded with soot, or carbon, and 

 the light was only a little better 

 than before. M. Argand and his 

 brother were, one night, sitting 

 at a table, their lamp, 6, burn- 

 ing dimly before them, when 

 the latter took up the neck of a 



315. 



broken flash, 6a, and playfully put 

 it over the flame, which immedi- 

 ately became clear and brilliant. 

 Argand jumped up in an ecstacy 

 of delight, for he at once saw 

 his invention perfected. 



So, many hundred years passed away, with- 

 out any material improvement in the means of 

 illumination, because the nature of the atmos- 

 phere was unknown, and the process of com- 

 bustion not understood. What was needed to 

 perfect the luminosity of flame was a greater 

 supply of oxygen, so presented to the flame 

 that it shoula not materially diminish its heat, 

 but should bo^in sufficient abundance to in- 

 stantly combine with the carbon and hydrogen 

 of the wick and oil. The source of oxygen is 

 the air ; and when M. Argand's brother acci- 

 dentally set a glass over the circular wick of 

 his lamp, he cut off the great body of cold air, 

 and brought into close contact with the flame 

 a thin but rapid stream of air, which became 

 instantly heated, and thus, on the inside of the 

 hollow wick, and on its outside, wilhin the 

 circle of the glass, a stream of warm oxygen 

 was supplied, the wick and oil were perfectly 



4 



consumed, smoke prevented, and light improved. 

 Let those who pursue useful discoveries never 

 despair ; they know not how near they may be 

 to the consummation of their wishes. When 

 disappointment appears to overshadow them, 

 let them think of M. Argand and his lamp ! 



The value of the Argand lamp has been 

 greatly augmented by the discovery of oils, 

 adapted for illuminating purposes, in an end- 

 less variety of substances. We obtain oil from 

 the fat of whales, 114, walruses, 115, porpoises, 

 116, seals, and fishes of various kinds ; also 

 from the vegetable kingdom, from the nuts and 

 seeds of trees and plants. We obtain also vo- 

 latile oils from the wood of trees, such as cam- 

 phine from the pine and larch; naphtha, from the 

 tar of coals, which is produced during the ma- 

 nufacture of gas ; and a fluid like coal-naphtha 

 is obtained by the distillation of oily matters 

 that exude from the earth. Whichever of these 

 substances may be employed for the purpose 

 of lighting, its illuminating power is greatly 

 improved by being burnt in a lamp upon the 

 Argand principle. 



Gas has been known, but not 

 understood, from very early ages. 

 Ancient his- 7 

 tory mentions 

 that in Greece 

 there were al- 

 tars, 7, lighted 

 by fires which 

 flowed from 

 the earth, and 

 were made sa- 

 cred to the 

 gods. When 

 Alexander arrived at Ecbafcana, 

 he saw a gulf of fire, which 

 streamed continually. This is 

 supposed to have been of naphtha. 

 The holy fires of Baku, near the 

 Caspian Sea, had a similar origin. 

 There are also springs of inflam- 

 mable vapour in North America, 

 and in other parts of the world. 

 The Chinese were the first to 

 turn gas to an economical use; 

 they collected that which escaped 

 from the earth in the neighbour- 

 hood of Pekin, and used it for 

 lighting streets and houses ; they 

 employed bamboos as gas-pipes, 

 8, and, to prevent the former 



316. 



