78 



WISCOlN^'SIlSr ACADEMY SCIENCES, ARTS, AND LETTERS. 



temperatures. The vapors are condensed m an iron coil passing- 

 throagli water and collected in separate reservoirs. The products- 

 of the distillation taken in order, as they are driven oif, are as fol- 

 lows: 



Name. 



Gasolene 



Naptha 



Benzene 



Kerosene 



Mineral sperm oil 

 Lubricating oil .. . 



Rhigolene is a ver}^ volatile hydro-carbon, produced by the re- 

 peated distillation of gasolene. In consequence of its rapid evapor- 

 ation, its boiling point being but 65^^ F., it is used in surgery for 

 producing " local anajsthesia." Paraffine, another product of petro- 

 leum, is a solid. It is used principally in the manufacture of can- 

 dles, chewing gum, and water-proof cloth. 



About ten per cent, of the native petroleum consists of gasolene, 

 naptha, and benzene. They pass from the still first, and are nearly 

 valueless, being sold for from five to ten cents per gallon. All read- 

 ily ignite at ordinary atmospheric temperature, therefore are highly 

 dangerous for illuminating purposes. After the light hydro-carbons 

 have been driven off, the remaining fluid in the still is generally 

 transferred to smaller retorts, the temperature raised, and safe ker- 

 osene distilled. A heavy black residue remains, which is princi- 

 pally manufactured into paraffine and lubricating oil. On aecounr 

 of the poor market for the light oils, and as they afford e^ven a more 

 brilliant flame than safe kerosene, there is a strong tendency on the 

 part of unscrupulous manufacturers to commence the collection of 

 burning fluid before the less dense oils have entirely passed off. This 

 is the primary cause of the many fatal accidents that yearly occur 

 from the use of kercseue. 



Kerosene oil has no constant composition. Like petroleum, it 

 consists of a great number of liquid hydro-carbons. Most of the 

 higher combinations of these elements found in kerosene, have a 

 low specific gravity, and are very volatile. They pass off in vapors 

 at comparatively low temperatures. As a burning fluid contains a 

 large or a small proportion of these volatile compounds, it is said 



