1869.] Mining. 141 



years is about 76?. Is. per man. Yet the "thirst for gold" levels 

 men from all parts of the world to endure all the privations and 

 the hardships of a gold-miner's life for this miserable reward. The 

 value of the metals and minerals raised in the colony of Victoria 

 since the discovery of the gold-field has been estimated as 

 follows : — 



£ 



Gold, 33,910,0521 oz 135,643,811 



Silver, 12,591 oz. 18 dwts 3,460 



Tin 195,045 



Copper 4,673 



Autimony 30,426 



Coal, 1933 tons, at II. 10s. per ton . . . . 2,899 



Lignite, 235 tons, at 17s. 6d. per ton . . 205 



Kaslin, 1757 tons, at il. per ton . . . . 7,028 



Flagging 18,663 



Slates 508 



Magnesite, 6^ tons, at 21. per ton ... . 12 



Diamonds, about 80 carats 80 



Sappliii-es 150 



Total value ,. .. £135,906,960 



The quantity of gold exported in 1867 was 1,433,687 oz., of 

 which 560,527 oz. were obtained from quartz veins, and 873,160 oz. 

 from alluvial workings. 



The explosions of fire-damp in some of the coal mines of 

 France has naturally drawn attention to the subject of ventilation. 

 M. Galy-Cazalat, who has brought the matter before the Academie 

 des Sciences, proposes the construction of vertical air-pits, the 

 purpose of which would be to draw ofl' the carburetted hydrogen 

 as rapidly as it is formed, and thus prevent its mixing with the air 

 of the mine. These " cheminees d'asinration" as he calls them, 

 will scarcely require very special description, the whole plan really 

 resolving itself into a greatly increased number of shafts, by which 

 the air in every part of the mine may be rapidly changed. There 

 can be little doubt that great advantages would arise from such a 

 system ; but in the large and deep coUieries of this country there 

 are many serious difiiculties standing in the way of its introduction. 



M. Delaurier has brought before the Academy of Sciences a 

 plan for destroying fire-damp in coal-mines. He proposes to place 

 copper conductors of considerable thickness in the galleries; these 

 are to be broken at intervals, and united by means of very thin 

 gold wire, which is to be covered with sulphur. By passing a 

 strong current of electricity through those conductors, the sulphur 

 is ignited, and if any fire-damp be present it will be fired. This 

 idea is by no means new. The Academy is said to have spoken 

 approvingly of the proposed plan ; but all coincided in the opinion 

 that regular and powerful means of ventilation could in no case be 

 dispensed with. The combustion of the Jire-damjp would produce 



