30 THE PRODUCTION AND USE OF LIGHT 



laws which forbid the sale of oil as illuminating oil, or kero- 

 sene, which has a flashing point lower than about 110F. or 

 a burning point lower than about 150F. This is the most 

 important of all of the tests which the inspector applies to 

 kerosene. 



The better qualities of kerosene have a flashing point of 

 120F. to 140F. If a lighted match be dropped into it, the 

 flame is extinguished. It has no unpleasant odor and burns 

 up completely without charring the wick of the lamp. Such an 

 oil is obtained by rejecting the first of the distillate after the 

 boiling point of the petroleum has reached 150C. and also 

 the last portion just before the boiling point reaches 300C. 

 This choice distillate is then carefully purified. 



A fair quality of oil is obtained by using all of the distillate 

 from 150C. to 300C. and carefully purifying it. The 

 cheaper grades of oil contain larger amounts of the portions 

 rejected from the higher grades. They therefore have low 

 flashing and burning points, and char the wicks. 



34. Use of Kerosene in Kindling a Fire. If instead of catch- 

 ing on fire itself a good quality of kerosene will put out a burn- 

 ing match, how is it that kerosene may be used as a kindling in 

 starting a fire? It is a common thing for people to dash a 

 little kerosene upon the fuel in a stove when starting a fire. 

 Can you readily start a coal fire by the use of kerosene alone 

 as kindling? Why does kerosene ignite so much more readily 

 when poured upon wood or paper than when poured upon 

 coal? Is it ever safe to use kerosene as kindling when starting 

 a fire? These and other questions which may arise are easily 

 answered by remembering that kerosene vapor burns only when 

 the kerosene is heated to its burning point. 



When the oil is poured upon wood, especially if the wood is 

 splintered or in the form of shavings, it becomes an easy matter 

 to heat small portions of the oil which saturate the smaller 

 splinters or shavings to the burning point. When the oil lies 

 spread as a thin coat over the chunks of coal it is difficult to 

 raise any portion of the oil to its burning point, unless the coal 



