250 



THE SCIENTIFIC PAPERS OF 



TABLE II. 

 ORDINARY FURNACE. 



It will be observed that the ordinary furnace received charges 

 of 484 Ibs. each, and yielded on an average 426 Ibs., representing 

 a loss of 12 per cent., whereas the gas furnace received charges 

 averaging 424 Ibs., and yielded 413 Ibs., representing a loss of less 

 than 2'6 per cent. 



It is important to observe, moreover, that the gas furnace turned 

 out eighteen heats in three shifts per twenty-four hours, instead of 

 only twelve heats per twenty-four hours, which was the limit of 

 production in the ordinary furnace. 



This rate of working was attained without the employment of 

 any arrangement for heating the pig iron before charging it into 

 the furnace, the heating chambers at the ends not having been 

 used. The adoption of the plan of heating the metal beforehand, 

 a system already extensively in use both in this country and on the 

 Continent, effects a further saving of ten to fifteen minutes in the 

 time required for working each charge, as well as a considerable 

 economy in fuel. 



The quality of the iron produced from the gas furnace was 



