PETROLEUM 371 



accomplished only when it is mixed with the atmosphere under 

 high pressure and exploded in the cylinder direct, in which 

 case the costly, troublesome, and wasteful boiler will no longer 

 be necessary. 



During the year 1902 the U. S. navy made some very 

 interesting experiments with petroleum as fuel, which were 

 conducted by a special division of the bureau of steam engi- 

 neering knowTi as the Hquid fuel board, under the direction 

 of Rear Admiral George W. Melville, chief engineer U. S. navy. 



Natural lubricating petroleum of the finest grade is often 

 found in the higher strata of the productive series at shallow 

 depths below the earth's surface. It is usually associated 

 with more or less salt water, usually ranges from 32° to 34° 

 Baume, is not affected, so far as fluidity is concerned, by a 

 temperature of zero or below, and commands a higher price 

 than any other variety of natural petroleum. 



The petroleum lubricants differ according to the crude 

 petroleum from which they are made. The chemical composi- 

 tion of crude petroleum from different localities is not the same, 

 showing either that the materials used in its preparation in 

 the earth var^^, or that by filtration through different strata 

 different combinations are formed. The largest production 

 of natural crude lubricating petroleum is from the neighbor- 

 hood of Franklin, Pa., which has long been celebrated for the 

 production of the finest natural lubricating petroleum found 

 in the world. 



There is also a large amount of lubricating oil manufac- 

 tured from Pennsylvania crude petroleum, some of which is 

 mixed with the natural product. No other lubricatmg petro- 

 leum is equal to that produced in the Appalachian field. Its 

 reputation is world wide. Many railroads and steamship 

 lines use it exclusively; the railroads using it in the United 

 States operate 97 per cent of the total mileage. 



Years ago the process of distilling natural mineral hydro- 

 carbons was being perfected and vigorously pushed in the 

 eastern states, and cannel shale was imported from England 

 and distilled at refineries near Boston and Portland. On the 

 Allegheny river near Freeport, Armstrong county and Dar- 

 lington, Beaver county, Pa. ; in Ohio, West Virginia, Western 



