June, 1841.] 43 



in action ; another is nearly completed, a third is partly finished, 

 and the foundations of a fourth are prepared. 



The ore used at those furnaces is mined at Irondale, 7 miles 

 eastward of the works, on the line of the canal, and is found to 

 yield in practice 65 per cent, of pig metal of a lively grey colour, 

 soft, and easily wrought, though not remarkably tough. The an- 

 thracite hitherto used is that from the Lehigh, chiefly from the 

 middle coal pit, and according to their experience hitherto, a decid- 

 ed preference is given to the Beaver Meadow coal. The hot blast 

 is employed at a temperature of 600 degrees and upwards. The 

 quantity of coal required within the furnace to make one ton of 

 iron is 22 cwt. ; that for heating the blast, about 4 cwt. The air is 

 delivered to the furnace under a pressure of 3 lbs. to the square 

 inch. The amount of blast furnished by the engine is 4071 cubic 

 feet per minute ; which as the furnace makes 8 tons per day, gives 

 a little more than 25 tons of air urged through the bellows for every 

 ton of iron produced. But the air heating ovens are supposed to 

 receive about one tenth of this amount v and nearly an equal portion 

 is believed to be wasted through apertures in the tubes leading to 

 the engines. If this estimate be correct, the quantity of blast 

 actually delivered to the furnace will be 20 tons per ton of pig 

 metal produced ; a quantity corresponding with what has been 

 found necessary both from theory and from experience in other 

 anthracite furnaces. 



