THE CONQUEST OF NATURE 



of great simplicity, yet one which gave such results that 

 it replaced the candle as a unit for measuring the illumi- 

 nating power of different sources of light. 



These various burners should not be confused with 

 the modern burners of the ordinary kerosene lamps. 

 Mineral oils had not as yet come into use for illumi- 

 nating purposes, except as torches or in simple lamps like 

 those of the Romans, as refining processes had not been 

 perfected, and the smoke and odors from crude petro- 

 leum were absolutely intolerable in closed rooms. 



Many other substances were tried in place of the heavy 

 oils, such as the volatile hydrocarbons and alcohols, but 

 with no great success. Early in the nineteenth cen- 

 tury a lamp burning turpentine, under the name of 

 "camphine," was invented that gave a good light and 

 was smokeless; but like most others of its type, it was 

 dangerous owing to its liability to explode. And it 

 was not until methods of refining petroleum had been 

 improved that " mineral-oil lamps" the predecessors 

 of the modern type of lamps came into use. 



The invention of this type of lamp was a relatively 

 easy task a simple transition and adaptation as proc- 

 esses of refining the oil were perfected. The principle 

 of combustion was, of course, the same as in the Argand 

 type of lamps burning animal and vegetable oils; but 

 mineral oils are of such consistency that capillarity 

 causes an abundant supply of oil to rise in the wick, so 

 that clockwork and spring devices, such as were used 

 in the Carcel lamps, could be dispensed with. 



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