MINERAL RESINS 97 



and consequently the project of employing it in the arts was 

 abandoned. 



Asphaltum is a constituent of the kind of black varnish 

 called Japan. It is used in France in forming a cement for 

 covering .the roofs'and lining water cisterns. A limestone, 

 thoroughly dried, is ground up fine and stirred well in a ves- 

 sel containing aVout one-fifth its weight of hot melted bitu- 

 men. It is then cast into rectangular moulds, which are first 

 smeared with loam to prevent adhesion. When cold, the 

 frame of the mould is taken apart and the block removed. 

 \ Petroleum is used in Birmah as lamp oil ; and when 

 mixed with earth or ashes, as fuel. Naphtha affords both fuel 

 and light to the inhabitants of Batku on the Caspian. The 

 vapor is made to pass through earthen tubes and is inflamed 

 as ii passes out and used in cooking. The spring near 

 Amiano is used for illuminating the city of Genoa. Both 

 petroleum and naphtha have been employed as a lotion in 

 cutaneous eruptions, and as an embrocation in bruises and 

 rheumatic affections. Naphtha is often substituted for oil in oil 

 paint, on account of its drying quickly. It is also employed 

 for preserving the metals of the alkalies, potassium and 

 sodium, which, owing to their tendency to unite with oxygen, 

 cannot be kept in any liquid that contains this gas. 



The petroleum or Seneca oil of western New York, Penn- 

 sylvania and Ohio, as it appears in the market, is of a dark 

 brown color, and a consistency between that of tar and 

 molasses. 



The following are the names of other kinds of fossil resin or wax: — 

 Fossil Copal, Middletonite, Piauzite, which are resinous and nearly or 

 quite insoluble in alcohol ; Guyaquillite and Berengelite, from South 

 America, resinous and soluble in alcohol like Retinite ; Scheererite, 

 Hatchetine, Dysodile, Hartite, Ixolyte, Ozocerite, Fichtelite, Konlite, 

 Branchite, found with coal, especially brown coal, and resembling wax 

 or tallow. Idrialine is grayish or brownish black with a grayish luster, 

 and occurs at the Cinnabar mines of Idria. 



CLASS IV.— SULPHUR. 



Sulphur exists abundantly in the native state. It occurs 

 , combined with various metals, forming sulphurets and sul- 

 phates ; and the sulphurets especially are very common ores. 

 The sulphuret of iron is common iron pyrites , sulphuret of 

 copper is the yellow copper ore of Cornwall and other re- 

 gions ; sulphuret of mercury is cinnabar, the ore from which 

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