56 FIRESIDE SCIENCE. 



hands. The light naphthas which have been spoken 

 of as known in commerce tinder the names of 

 benzine, benzoline, gasoleine, etc., are very vola- 

 tile, inflammable, and dangerous. They, however, 

 in themselves, are not explosive ; neither are they, 

 when placed in lamps, capable of furnishing any gas 

 which is explosive. Accidents of this nature are 

 due entirely to the facility with which vapor is pro- 

 duced from them at low temperatures. But the 

 vapor by itself is inexplosive ; to render it so, it 

 must be mixed with air. A lamp may be filled 

 with bad kerosene, or with the vapor even, and in 

 no possible way can it detonate, or explode, unless 

 atmospheric air has somehow got mixed with the 

 vapor. A lamp, therefore, full, or nearly full of 

 the liquid is safe ; and also one full of pure warm 

 vapor is safe. Explosions generally occur when the 

 lamp is first lighted without being filled, and also 

 late in the evening, when the fluid is nearly ex- 

 hausted. The reason of this will readily be seen. 

 In using imperfect or adulterated kerosene, the 

 space above the line of oil is always filled with 

 vapor ; and so long as it is warm, and rising freely, 

 no air can reach it, and it is safe. At bedtime, 

 when the family retire, the light is extinguished ; 

 the lamp cools, a portion of the vapor is condensed ; 

 this creates a partial vacuum in the space, which is 

 instantly filled with air. The mixture is now more 



