752 Transactions of the American iNSfiTUTE. 



New Oil Gas Light. 



Dr. D. D. Parmlee exhibited Mr. Theodore Clouffh's oil iras Hsrht, 

 and read the following paper on that subject : 



It is deemed necessary, before describing Mr. Clongh's invention, 

 to explain, in a short and general manner, tlie nature of petroleum 

 bui-ning oil, which he employs ; and, also, the other products derived 

 from crude petroleum, in their relation to artificial illumination ; for 

 the reason that it is common to discover the want of a proper under- 

 standing of this subject by those, who, in most other respects, are of 

 acknowledged talents. 



Crude petroleum varies in different localities in several physical 

 and chemical respects. In some instances it is a heavy parafline oil, 

 liolding paraffins in solution to an extent which adapts it to purposes 

 of lubrication. In other localities, more limpid oil is found, consist- 

 ing of a gradation of liydrocarbons varying from about thirty-nine 

 degrees to ninety-five degrees Bai\me. For commercial purj)Oses 

 these products are separated by distillation into, first, " gasoline " of 

 specific gravity' seventy degrees to ninety degrees Baume ; secondly, 

 " naphtha " of fifty-nine degrees to seventy degrees ; thirdly, oil 

 for burning, which will answer the tests adopted by the United 

 States government, and which is known as the fire test. 



The apparatus usually employed for testing oil is made of metal 

 and glass, consisting of a cup holding about a gill, resting in a water 

 bath which is situated immediately over a spirit lamp. The oil to be 

 tested is put into the cup and the bulb of a standard thermometer is 

 ■immersed in it. The lamp is next lighted, and the water bath gradu- 

 ally heated. At every degree of the elevation of the temperature of 

 the oil as indicated bj' the thermometer, a lighted taper is rapidly 

 passed over and near the surface of the oil in order to learn precisely 

 at what degree any light products which may l)e contained in it are 

 volatilized. This is known by a momentary flame and flash of light 

 over the surface of the oil. The elevation of temperature is continued, 

 and the trials repeated until a continuous flame is formed. The 

 temperature at which this occurs is the commercial fire test. The 

 law requires that this burning shall not take place at a temperature 

 less than 110 degrees Fahr. Oil which will stand this test has been 

 decided to be safe for general use for illumination, transportation and 

 storage, under the exercise of those precautions required in handling 

 all combustible liquids. 



The test above described when applied to naphtha at ordinary 



