644 PETROLEUM 



the seventeenth century. The disulphate of quinine is largely prepared from this 

 bark, of which we imported in 1873 as follows : 



Quantity Value 



Cwts. 



From France 1,110 7,845 



Central America 1,228 12,280 



New Granada 11,843 106,617 



Ecuador 4,668 44,597 



Peru 5,829 74,643 



Chili 1,782 23,453 



Brazil 146 1,387 



Other countries 1,845 14,798 



Total 28,451 285,620 



Of which we re-exported 11,424 cwts. to the value of 71.304Z. 



PETAUTE, from irfToXov, a leaf. The mineral in which lithia was first dis- 

 covered by Arfvedson. Petalite occurs in the iron mine of Uto, Stockholm ; near 

 York, on the north coast of Lake Ontario ; at Bolton, Mass., U.S. ; and at Elba. Its 

 composition is, according to Kammelsberg: silica, 77'79 ; alumina, 18'58; lithia, 

 3-30; soda, 1-19 = 100-86. 



PETROLEUM. (Petrole, Fr. ; Steinbl, Ger.) This term is applied to several fluid 

 bituminous substances, found in a great number of different localities, in rocks of very 

 dissimilar ages, and which were formerly known as Persian naphtha, or rock-naphtha. 

 (See NAPHTHA.) As it, however, forms only one of a numerous class of analogous com- 

 pounds, it will be convenient to take a general view of the whole class of bituminous 

 minerals occurring in nature. Starting with the liquid compounds, which, as a rule 

 are, in composition isomeric with olefiant gas, and may be represented by the formula 

 C?iHw, the diminution of hydrogen is accompanied by an increase of density, until we 

 reach the more bituminous varieties of coal. The following table, by Dr. Sterry Hunt, 

 represents the intermediate steps of this series ; the analyses are computed with 24 

 equivalents of carbon, in order to compare them with cellulose, C' M H 20 O 20 : 



Liquid bitumens ; general composition . 



Rangoon petroleum . 



Elastic bitumen or Elaterite ; Derbyshire 

 Asphalt, Bastennes .... 



Naples 



Mexico 



Idrialine 



Albertite or Albert coal ; New Brunswick 

 Bituminous or resinous lignite 



C 24 H 24 - 

 C M H 26 - 

 C 24 H 22 0-* 

 C 2 * H 18 0- 7 

 C 24 H 15 O 2 - 



C 24 H 17 2 ' 



C 24 H 8 - 

 C 24 H 18 2< 

 C H ls s - 



re 21 H* o 



Bituminous coal, extremes of composition . . 'iC 24 H l O 4 



From the above table, it will be seen that certain bitumens, such as Idrialine, differ 

 but slightly in composition from bituminous coals, and in reality it is very difficult 

 to draw a decided line between them. The questions as to whether certain Scotch 

 cannel coals and the Albert coal of New Brunswick, are to be considered as coal or 

 not. have been discussed at great lengths before courts of law, without leading to any 

 satisfactory definition. Roughly speaking, the characters of fusibility and solubility 

 in benzole and sulphide of carbon are to be relied on as distinguishing the solid 

 bitumens from coals. 



According to Boussingault, asphalt is a dark brown or pitchy-black substance, 

 fusible at the temperature of boiling water. At lower temperatures, when perfectly 

 solid, it breaks with a well-marked conchoi'dal fracture. Hardness, 2 ; specific gravity 

 I'l to 1*2. It becomes negatively electric by friction, giving out a strong and charac- 

 teristic bituminous odour. When asphalt is treated with anhydrous alcohol, about 

 5 per cent, of a resin is extracted, which is called by Boussingault Petrolete. From 

 the remaining 95 per cent, insoluble in alcohol, ether dissolves 70 per cent, of a 

 black resin, giving a brown solution. The whole of the remaining 25 per cent, is 

 soluble in rock-naphtha or ethereal oils, and has been termed Asphaltene. Its per- 

 centage composition is: carbon, 75-5; hydrogen, 9'D ; and oxygen, 14'8 or approxi- 

 mately of the atomic formula, C 2 * H 20 O 4 , which, according to the preceding table, is 

 intermediate between asphalt and elaterite. 



Among the more important localities of bituminous matters, are the following : 

 Sandstones and limestones filled with asphalt, in greater or less abundance, of the age 

 of the Molasse, or Middle Tertiary period, are found at Soyssel, in the French depart- 



