Mai 1, 1865.] THE TECHNOLOGIST. 



GOLD AND ITS ALLOYS. 451 



contracts for that coal were in few hands, the manufacture of the oils 

 was, irrespective of Young's patent, almost a monopoly. The discovery 

 of the Flintshire cannel has altered all this ; and although the supply 

 of coal is, and probably will remain, limited, it has nevertheless opened 

 the trade, and so far broken down the monopoly, to the advantage of 

 the trade at large, and also of the public, who are the consumers. 



The mineral oils which are obtained, both from the Boghead coal 

 and the Flintshire cannel, are of the kind known as paraffin oils, and 

 differ entirely in their chemical constitution from the oils which are 

 produced by the distillation of common bituminous coal, or coal tar. 

 Their leading feature is, that they contain the peculiar crystalline sub- 

 stance called paraffin, now employed for sperm in candle-making, with 

 which they are identical in composition, although different from it in 

 physical structure. The manufacture of these oils is now a great esta- 

 blished branch of industry, employing large capital and a great amount 

 of business energy. 



The discovery of the liquid petroleum of North America, had at 

 one time apparently placed the trade in the hands of the Americans ; 

 but extended experience has shown that the oils can be produced at a 

 cheaper rate from our own coals, provided a supply of the latter, of the 

 proper quality, can be obtained. This problem the discovery of the 

 Flintshire cannel has favourably solved so far, and there can be little 

 doubt that the commercial enterprise which it has directed into the 

 district will succeed in keeping us independent of foreign supplies to 

 that extent which is necessary to the maintenance of the trade in a 

 state of wholesome freedom from the trammels which a close market 

 never fails to impose. 



GOLD AND ITS ALLOYS. 



The following particulars on the subject of gold, with special reference 

 to the trade in that metal, are supplied for popular information. 



Pure or fine gold is distinguished by its rich yellow colour, in con- 

 nexion with a high degree of softness and malleability ; it is heavier 

 than any substance in nature except platina, gold being 19-4, and after 

 hammering or pressure 196, heavier than water, whereas platina is 

 21-5. 



An alloy of silver renders it pale and greenish, and a small propor- 

 tion of that metal is sufficient to produce the effect in a remarkable 

 degree, hence the paleness of gold found in California and New South 

 Wales. Copper on the other hand deepens the colour, and by an alloy 

 of copper and silver together, a colour approximating to that of pure 

 gold may be retained ; both these metals, however, confer a great degree 

 of hardness, the absence of which, together with the weight, will 



