THE SOURCE OF LIGHT, HEAT, COLOUR, ETC. 



157 



I have compiled the following table from various authentic sources, and 

 the reader will therein see at a glance the main chemical differences of the 

 bitumens of commerce. 



Petroleums - 



Ojokerite 

 Asphalturn (Peru) - 



,, (Auvergn) 

 Elastic Bitumen - 



Carbon. 



Hydrogen. 



88'3 



11-9 



88-7 



12-6 



78-50 



880 



86-07 



13-95 



88-66 



9-65 



76-13 



9 41 



52-25 



7-50 



Oxygen. 



2-60 



Nitrog 



0-011 

 0-04 

 1-65 



1-69 



10-34 

 40-10 



2-32 

 0-15 



Ashes. 



8-45 



1-80 



Sp. gr. 



0-87 



0-94 



1-1 



to 



1-2 



1-23 



As an illustration of the manufacture of bitiimens, I may just mention 

 that carried on at Price's Candle Company, under the able superintendence 

 of Mr G. F. Wilson, from Rangoon Tar. The tar subjected to distillation by 

 super-heated steam, yields up in succession the following products : 1st, 

 a light fluid, somewhat analogous to Benzole, termed by the makers, Sher- 

 woodole, and sold as a valuable detergent ; 2nd, a burning oil called Bel- 

 montine, with scarcely any colour, and hardly perceptible smell, and cer- 

 tainly the very best Paraffine oil yet presented to the public ; 3rd, a heavier 

 oil, containing doubtless a small quantity of solid paraffine in solution ; 

 this product mixed with some other oils is found highly serviceable as 

 a lubricant ; 4th, an oil containing much solid paraffine, which latter 

 substance, on being separated by pressure is manufactured into a beautiful 

 class of candle. 



There is one singular feature connected with the manufacture of the 

 fossil hydro-carbons, whether coals, peats, or bitumens, which is deserving 

 of notice. The raw materials are simply compounds of hydrogen and 

 carbon, and the products are likewise the same, the sole difference being in 

 their chemical proportions. Such being the case, it becomes a question, 

 how far, if at all, the results can be influenced by improved or altered 

 methods of manufacture, so as to secure a larger supply of the more 

 valuable, and diminish proportionately those in less demand, or less 

 remunerative. 



It is subject-matter for no mean measure of gratitude, that Great Britain 

 engrosses to her share so large a proportion of the fossil hydro-carbons ; the 

 coals of England, Scotland, and Wales ; the peat-bogs of Ireland ; the 

 petroleum of Rangoon, Canada, and Barbados, as well as the pitch of 

 Trinidad, will furnish us with raw materials sufficient to supply all Europe 

 and Asia, if need be, with hydro-carbon productions. 



(To be continued.) 



