686 



PETROLEUM. 



crude petroleum. There are, therefore, three 

 distillates possible and in a general way three 

 qualities of illuminating oil. They consist of 

 oils that are pure distillates, oils that are 

 cracked, and mixtures of the two. Whatever 

 the distillate may be, about 1,200 barrels are 

 pumped into a tank 40 feet high and 12 feet in 

 diameter, called an agitator, which rests upon 

 a base of timber: 6,600 pounds of strong oil 

 of vitriol are then forced into the tank from 

 a closed cistern into which the carboys are 

 emptied. The cistern is closed, and air is 

 forced into it until the pressure is sufficient to 

 drive the acid into the tank. The distillate 

 and acid are then thoroughly mixed by air 

 forced into the bottom of the tank. After the 

 acid has been drawn off, the oil is washed with 

 water, then with a solution of caustic soda, 

 again with water, and lastly with caustic am- 

 monia, which is supposed to remove the last 

 traces of sulphur compounds. The oil is then 

 discharged into settling-tanks through a per- 

 forated perpendicular pipe, in a fine spray, 

 which causes any remnant of very volatile oil 

 to be evaporated and removed. In these set- 

 tling-tanks, beneath skylights, the last traces of 

 water settle and leave the oil clear and almost 

 colorless. It is then pumped into tank-cars or 

 into storage tanks. 



The residue in the still is worked over by 

 distillation and mixture into lubricating oils 

 and paraffine. Lubricating oils are prepared 

 by a great variety of processes for as great a 

 variety of purposes. For lubricating the inte- 

 riors of steam cylinders oils are deprived of 

 their more volatile constituents by exposing 

 them to the sun on the surface of water in 

 shallow tanks. Sometimes the water is heated 

 by a steam-coil. For the same purpose, oils 

 are deprived of their naphtha and illuminating 

 oil in a still, and the residue, called " reduced 

 oil," is then run out of the still. Sometimes 

 the reduced oil is filtered through animal char- 

 coal or other material, and deprived of much 

 of its odor and color. Other oils of less densi- 

 ty which in the ordinary distillation of petro- 

 leum " without cracking " come off between 

 illuminating oil and the heavy oils next to 

 residuum are treated in a still by means of 

 superheated steam in such a manner as to re- 

 move the volatile cracked products invariably 

 resulting from the first distillation, leaving in 

 the still an oil of high boiling-point, almost en- 

 tirely without tnste or odor. These oils are 

 called " neutral lubricating oils." The oils that 

 are distilled from them after treatment have 

 been called " mineral sperm," and are distin- 

 guished from ordinary illuminating oils by 

 their very high boiling-point and fire-test. 



Another class of petroleum products of su- 

 perior quality has been prepared by distilling 

 the crude oil in a vacuum apparatus, by which 

 the effects of cracking are prevented. These 

 oils have been largely used in treating leather. 

 When crude petroleum is carefully distilled 

 without cracking until the residue in the still 



has the consistence of jelly at ordinary tem- 

 peratures, and the residue while hot filtered 

 through animal charcoal, the product is an 

 amorphous paraffine of a semi-transparent pale- 

 brown color. This substance has been widely 

 introduced into pharmacy as petroleum oint- 

 ment, and is used as a basis for medicated 

 ointments, being found greatly superior to 

 preparations of lard and spermaceti on account 

 of its freedom from rancidity. The same 

 preparation is also widely consumed under the 

 names of cosmoline, vaseline, petrolina, etc. 



The use of petroleum prior to the past thir- 

 ty years for illuminating, though centuries 

 old, was confined to various rude attempts to 

 burn the crude oil in the regions in which oil- 

 springs occurred in greatest abundance. In 

 Burmah, the Rangoon tar was burned in earth- 

 en lamps of the simplest construction possible. 

 In Persia pencils of dried camel's dung, which 

 served as a wick, were immersed in the oil, in 

 vessels that were placed in niches in the houses, 

 the niches communicating with the open air. 

 In Italy the fluidity of the oil made possible its 

 combustion in street-lamps. In the valley of 

 Oil Creek in Pennsylvania the crude petroleum 

 was used in a vessel resembling a tea-kettle, 

 the wick protruding from the nozzle, for light- 

 ing salt-well derricks and saw-mills, long be- 

 fore the introduction of coal-oil had suggested 

 the refining of the crude oil. 



Since 1854, when petroleum was first refined 

 in Pittsburg, Pa., refined petroleum has pene- 

 trated the most remote regions of the habita- 

 ble globe, until it has superseded almost every 

 other illuminating agent except coal-gas and 

 electricity. Under many conditions of place 

 and purpose, one serious objection lies against 

 its use, which has been found to require con- 

 stant legal and sanitary supervision. The va- 

 pors of the more volatile constituents of petro- 

 leum, when mingled with air in proper pro- 

 portion, form mixtures that burn with great 

 explosive violence. If these light oils, even in 

 very small proportion, are allowed to mingle 

 with illuminating oil, the mixture becomes un- 

 safe under the ordinary conditions of domestic 

 life, and frightful disasters have followed a 

 careless disregard of these facts. To insure 

 public safety, nearly all civilized countries and 

 most of the States of the American Union 

 have enacted laws intended to compel the use 

 of oils properly prepared. Their safety is de- 

 termined through tests designed to ascertain 

 the temperature at which any given specimen 

 of oil will give off a sufficient amount of vapor 

 to burn explosively when mingled with air. 

 The instruments and methods vary, but a suffi- 

 cient uniformity follows their use to insure a 

 generally uniform result, and in the main pro- 

 tect the public from unsafe oils. 



For many and obvious reasons, petroleum 

 can not generally compete with coal as a fuel. 

 There are localities, notably the Caspian region 

 and the Pacific Coast of North America, where 

 petroleum of inferior quality is abundant and 



