found in Urpeth Colliery, near Newcastle. 



399 





How obtained, or where. 



State at 60 deg. 



Density. 



Becomes solid 

 or liquid at 



Boils at 



Density of gas 

 or vapour. 



Sweet oil of wine. 



In preparing ether. 



Oily liquid. 



0-917 



Solid at 31 °F. 



536° F. 



p 



Solid oil of wine. 



Ditto. 



Prisms. 



0-980 



Liq. at 230° 



500 + 



? 



Solid oil of roses. 



In oil of roses. 



Crystalline 

 plates. 



p 



Ditto at 95° 



536°to572° 



p 



Paraffine. 



From wood, coal, and 

 animal tars. 



Ditto. 



0-87 



109° to 111" 



p 



? 



Naphtha. 



From natural wells, 

 and from coal tar. 



Liquid. 



0-75 to 0-78 



? 



i76°to212° 



2-833 



Methylene. 



Exists in wood spirit. 



Gas. 



0-4.903 



? 



p 



0-4903 



defiant gas. 



By heating alcohol 

 with twice its bulk 



Gas. 



0-9806 











of sulphuric acid. 







p 



p 



0-9806 



Faraday's light liq. 



By compressing oil 



gas. 

 Distilling ethal with 



Ditto. 



1-9612 



Liq. at 0° 



Below 32° 



1-9612 



Cetene. 



Oily fluid. 



? 



p 



527° 



7-844. 





phosphoric acid. 













Ozocerite, Hatche- 



Found native. 



Solid. 



0-8S5 to 0-955 



Liq. from 



250°to572° 



? 



tine, &c. 









102°" to 182° 







A glance at the second column of this table shows that several of these 

 substances are obtained from the products of the distillation of coal, and 

 though it has not been demonstrated that any of them actually exist ready 

 formed in the mass of the coal itself, yet the very low temperature at 

 which some of them are given off lends to this opinion a considerable de- 

 gree of probability. Reichenbach states that bituminous coal, by distilla- 

 tion with water, yields l - 320,000thof an ethereal oil, which is identical with 

 native naphtha ; and he concludes that the naphtha and petroleum springs of 

 Persia, India, Italy, and South America, have their origin in the slow dis- 

 tillation of large beds of coal, by the ordinary heat of the earth. The fos- 

 sil wax of Moldavia, and the hatchetine of England, are probably derived 

 from vegetable matter by a like agency. 



Naphtha is a comparatively dense fluid, requiring a temperature of up- 

 wards of 173° F. to boil it; and, therefore, unless present in large quan- 

 tity, it will rarely escape from the coal so rapidly, as alone to render the 

 atmosphere combustible ; but, suppose the very light liquid discovered in 

 oil gas to exist in the coal, it will at once escape as a highly inflammable 

 gas, and materially injure the atmosphere. Because such substances have 

 not hitherto been observed in the air of mines, we ought not hastily to 

 conclude that they do not exist, ready formed, in the great laboratory of 

 nature. The difficulty of detecting them in a limited portion of gaseous 

 matter will, probably, long present insuperable difficulties to the analytical 

 chemist, while the more we learn of the carbo-hydrogens the more likely it 



