C58 



PETROLEUM. OE EOCK OIL. 



the intermixed pitchy material already alluded 

 to, and perhaps, in certain cases, imperfectly 

 bituminized organic matters, sometimes also 

 compounds of sulphur, as well as finely-divided 

 carbon, sand, clay, <fcc. Owing to varying pro- 

 portions of the light and heavy component oils, 

 and of solids, which they contain, different spe- 

 cimens of crude petroleum will be found to have 

 every degree of consistency, from that bordering 

 on naphtha on the one hand, to that which ap- 

 proximates the condition of tar or soft bitumen, 

 on the other. Density alone, however, is not 

 an absolute criterion of the value of crude oils ; 

 although short of analysis or actual distillation, 

 it is that which must be, and in practice is, 

 chiefly relied on. The extreme range of den- 

 sity of the crude oils may be stated as from 

 about 52 to 20 B., corresponding to specific 

 gravities of from about .770 to .936. Among 

 the gases contained in or associated with crude 

 petroleum, as it exists in the natural reservoirs 

 in the earth, and in addition to the methyle 

 and ethyle hydrides, sulphydric acid gas (giv- 

 ing the sulphurous odor) is sometimes found ; 

 and olefiant gas, carbonic acid, and others, 

 may probably also be present in certain cases. 



It has already been seen, that when the rock 

 oils first come to the surface of the earth they 

 begin to set free both the gases and the vapors 

 of their more volatile components ; and these 

 changes go on to a considerable extent if the 

 oil is long exposed to the air, the evaporation 

 in particular becoming very great in summer, 

 and under exposure to a hot sun. The effect 

 of these changes is first to render the oil more 

 dense and thick, while its volume diminishes. 

 But in the longer exposure that follows when 

 the rock oils rise in springs, or escape from 

 crevices in rocks, and flow out upon the sur- 

 face of the elirth, a further change sets in ; the 

 oils which do not evaporate, to some extent 

 (according to Prof. T. S. Hunt) absorbing oxygen 

 from the air ; and they appear thus to acquire 

 more nearly the nature of resins, or of pitch. 

 Through the threefold change now indicated, 

 the naphthas and petroleums of all countries, 

 under the circumstances named, become con- 

 verted into the more solid (surface) bitumens ; 

 and it would appear that, by a continuance of 

 the same process, aided in some cases doubtless 

 by the pressure of strata subsequently deposited 

 above them, they may in time be changed to 

 the hardest asphalt. Still, among the qualities 

 distinguishing the materials now named from 

 all the sorts of coal proper are, that the former 

 only are almost completely fusible at a heat of 

 from about 212 to 220, and soluble in benzole 

 and bisulphide of carbon. Among remarkable 

 examples of the occurrence of bitumen or as- 

 phalt, may be named the viscous petroleum, or 

 mineral tar, of the island of Barbadoes ; the bit- 

 umen forming upon the waters and shores of 

 the Dead Sea (bitumen Judaicum, or "Jews' 

 pitch ") ; that of Pitch Lakes, the largest known 

 being in the island of Trinidad ; the chapapote 

 f Cuba ; ami the vertical seam of asphalt found 



in Eitchie Co., Va., near to the village of Cairc 

 and to Cave Eun, the waters of which flow 

 into the north fork of Hughes Eiver an un- 

 stratitied, black, and very hard bituminous 

 mass, about four feet in thickness, and reach- 

 ing to an unknown depth, and which yields 

 upon distillation from 80 to 90 per cent, of oil. 



For the statement of many points in con- 

 nection with the history of discoveries and 

 uses of rock oils, the mode of distilling and 

 purifying as now practised, the modes of burn- 

 ing refined illuminating oils of this and similar 

 character, precautions required in their use, 

 &c., the reader is referred to the articles COAL 

 PRODUCTS, NAPHTHA, and PETROLEUM, in the 

 NEW AMERICAN CYCLOPAEDIA, and to sections 

 of the articles on ILJXMINATIOX, in the volumes 

 of this CYCLOPEDIA for 1862 and 1863. See 

 also AXILLNE CoLqES, in this volume. 



Historical Items, with reference especially to 

 the use of Rock Oils for Illumination. As 

 early as 1830, works for distilling oils from bi- 

 tuminous materials were established in France, 

 and these are still in operation. In the exten- 

 sion of this manufacture, started somewhat 

 later in England and other parts of Europe, one 

 of the most influential pioneers was Mr. James 

 Young, of Glasgow, who commenced in the year 

 1847 distilling the petroleum of a spring in Der- 

 byshire, and, when this ceased to flow, turned 

 his attention, about the year 1850, to the dis- 

 tillation of peats, lignites, shales, &c., and espe- 

 cially of the so-called " Boghead cannel," and 

 whose works are probably still the first in Great 

 Britain. 



At a date much earlier, however, crude pe- 

 troleum was to some extent burned in lamps 

 by the settlers along the Little Muskingum 

 River, in the State of Ohio, the oil being ob- 

 tained from a well bored for salt near that 

 river. In 1819, Professor S. P. Hildreth, of 

 Marietta, found the oil so in use ; and in an arti- 

 cle upon the subject written in that year, but 

 published as late as 1826, he predicted that this 

 oil would yet be valuable for lighting the street 

 lamps of the future cities of Ohio ! But it was 

 the new element (practically speaking) of dis- 

 tillation, then being, or soon to be, introduced 

 elsewhere, that petroleum required, in order to 

 render it generally serviceable for illumination, 

 and for want of which it had in the main con- 

 tinued to be a" waste article for so many cen- 

 turies. 



In the year 1854, although to some extent 

 previously carried on here, the business of dis- 

 tilling coal and shale oils was in this country 

 inaugurated on a large and highly successful 

 scale by the " New York Kerosene Oil Co.," 

 the works of which, in the outskirts of Brook- 

 lyn (Eastern District), are still among the first 

 of the kind in the United States. 



The first deep well bored with a view to test 

 the existence of petroleum in strata below, in 

 sections where oil appears at the earth's sur- 

 face, was that undertaken by Col. E. L. Drake, 

 on Oil Creek, about one and a-half miles from 



