ILLUMINATION. 



521 



called the condenser. Heat is applied to the 

 retort, and from the open extremity of the 

 condenser, a light colored liquid of a strong 

 odor soon flows. This is naphtha, and is very 

 volatile and very explosive. Some refiners 

 mix it with the burning oil, and numerous ac- 

 cidents have resulted from such mercenary 

 indiscretion. It is usually run into a separate 

 tank. After the naphtha has passed over, the 

 oil used for illumination distils off. Steam is 

 now forced into the retort and the heavy lubri- 

 cating oil driven over. There now remains a 

 black, oily, tarry matter, sometimes used to 

 grease heavy machinery, and a black coke, em- 

 ployed as fuel. There are, therefore, five sub- 

 stances separated in this operation, but only 

 the first three are of any economic importance. 



The naphtha is used as a substitute for 

 turpentine in paints, or by repeated distilla- 

 tions the benzole is separated from it and em- 

 ployed to remove spots from fabrics. This, 

 however, is rather a drug in the hands of the 

 refiner. 



The burning oil (called kerosene, and in Eng- 

 land, paraffine), as it comes from the retort, is 

 of a yellow color, and in order to remove this, 

 it is placed in a large lead-lined cistern, and 

 agitated with about ten per cent, of sulphuric 

 acid. After the acid and the impurities have 

 subsided, the oil is drawn off into another tank 

 and agitated with four per cent, of soda lye. 

 This last operation is to remove any acid re- 

 maining with the oil, and' also to extract the 

 residue of the coloring matter. In fact it is 

 sometimes employed alone, and a very good oil 

 obtained. The oil is now agitated with water 

 to remove the soda lye, and is then ready for 

 consumption. The colorless oil is by no means 

 the most economical, but on the contrary more 

 light is obtained from the yellow article. 



The heavy oil is cooled down to 30 Fahr., 

 when the paraffine (solid) crystallizes out, and 

 is separated from the oil by pressing. It is 

 further puriSed by another pressing and by 

 alternate agitation, in a melted state, with Bol- 

 phuric acid and soda lye. It is then moulded 

 into candles. It is a curious fact that the com- 

 position of paraffine and of good coal gas is ex- 

 actly the same. 



In Egypt a substance derived from petroleum 

 was used in embalming bodies ; and in Persia 

 and the neighboring countries asphaltum is 

 used to cover the roofs of the houses and to 

 coat the boats. In France asphaltic pavements 

 have been successful in several cities, and for 

 the protection of stone no material is better 

 adapted. Mixed with grease the Trinidad as- 

 phaltum is applied to the sides of vessels, to 

 prevent the borings of the teredo, and with 

 quicklime it affords an excellent disinfectant. 

 Among the products of the distillation of petro- 

 leum are naphthaline and kerosolene. The 

 former is the substance from which is obtained 

 aniline, the base of the beautiful colors, mauve, 

 magenta and solferino. The latter has been 

 proposed as a substitute for chloroform and 



ether. Many other substances have been sep- 

 arated, but as yet none of them have been ap- 

 plied. As this is comparatively a new field, 

 many discoveries may be confidently expected 

 in it in the course of a few years. 



Farajfinc (or Kerosene) Oils. At the request 

 of the Manchester Sanitary Association, Mr. 

 Ch. O'Neil examined many specimens of par- 

 affine oils. About 25 of these were bought in 

 Manchester, 3 or 4 of them being from the 

 United States ; and there were besides ' 14 

 samples from oil wells in Pennsylvania and 

 Canada. One sample from London and another 

 from Liverpool formed with air an explosive 

 vapor at as low a temperature as 60 F., and 

 were to be considered as decidedly unsafe. 

 Three of the samples gave with air explosive 

 mixtures at 85 ; of the remainder, 4 formed 

 explosive mixtures at about 100 ; then 3 more 

 at about 120 D , and 20 by the tune of reaching 

 150. Of the last 20, 18 were manufactures of 

 one firm in Manchester, that of Mr. Young, all 

 whose oils were found safe ; 2 of them were 

 from America. Out of 32 samples, 20 were 

 pronounced safe ; 3 less so ; 9 dangerous. Some 

 of these oils, even of high specific gravity, are 

 dangerous specific gravity being thus shown 

 to be no test of safety. Neither is the boiling 

 point such a test ; since many substances of 

 high boiling points have still a very high diffu- 

 sive power ; coal naphtha, for example, which 

 boils at 260, can form an explosive mixture in 

 air, and almost instantly, at 32. 



The illuminating power of paraffine (kero- 

 sene) oil is remarkably high. One gallon of 

 Young's paraffine oil, weight about 8 Ibs., 

 will give, according to Dr. Letheby's experi- 

 ments, the light of 23| Ibs. of spermaceti can- 

 dles, or of 27 Ibs. of wax candles, or of 28^ Ibs. 

 of stearic candles, or of 40 Ibs. of the best tal- 

 low candles. 



For a valuable history of Petroleum or Rock 

 Oil, with an appended note on the chemical 

 composition of this oil and its relation to that 

 of various coals, peat, woody fibre, &c., by 

 Prof. T. S. Hunt, and also for a paper on the 

 " Explosibility of Coal Oils," by Mr. T. Allen, 

 of R. I., the extent of which papers is too 

 great to allow of a satisfactory abstract within 

 the limits of this article, the reader is referred 

 to the " Smithsonian Report," 1861. Mr. Allen, 

 it may be remarked, traces the great explosive- 

 ness of the coal or rock oils, where it exists, to 

 the fact of their not being entirely freed from 

 the more volatile and extremely inflammable 

 naphtha, benzole, benzine, &c., associated with 

 them. Since crude petroleum and coal oils 

 contain much naphtha, they partake in corre- 

 sponding degree of its dangerous properties; 

 and the careful and entire separation of all more 

 volatile components by distillation, in prepar- 

 ing the so-called "kerosene," or other oils for 

 burning, becomes a point of the highest im- 

 portance. 



In the autumn of 1862, the grand jury of 

 the city of New York, taking into considera- 



