.S7A' WILLIAM SIEMENS, F.R.S. 327 



looked upon tin- l>last furnace as requiring a fuel which would live 

 down to the crucible, and there perish. If they were to charge 

 graphite, they would get it all into the crucible, and have to tap 

 it out with the slag, unconsumed ; and what Professor Williamson 

 had just said showed the great resistance of hard coke to combus- 

 tion, and its great advantages in certain respects ; but they might 

 ha\v too much hardness and so make the coke imperishable in the 

 furnace. He had therefore proposed that before deciding upon 

 the proportion of anthracite, comparative trials should be made, 

 using coke containing a very large per ceutage of anthracite, 

 formed with pitch, and weaker coke containing only from 25 to 30 

 per cent, of anthracite, made without pitch. He had with him a 

 piece of coke containing 25 per cent, of anthracite and no pitch, 

 which appeared to him probably hard enough for their height of 

 furnace and their blast ; but he might be mistaken. It might be 

 that the harder coke gave still better results ; but he must say 

 that if the hardness exceeded a certain limit, he expected that a, 

 large amount of carbonaceous matter would come out with the 

 slag, and in fact, their experiments already showed that evil to 

 exist to some extent, but they had hardly been carried on for 

 a sufficient length of time to say definitely to what extent. 

 There could be no doubt whatever that the production of coke 

 of such hardness that it would resist the action of hot car- 

 bonic acid in the upper portion of the furnace and furnish 

 carbonizing material down to the very bottom of the furnace, 

 was a matter of very great importance. One result which had 

 been observed and which Mr. Hackney had not stated, as far 

 as he could gather from his paper, was this, that while they 

 were troubled with sulphur in using their ordinary coke, which 

 contained a good deal of sulphur, the sulphur disappeared as by 

 magic the moment the anthracite coke came down to the bottom 

 of the furnace, producing, in fact, No. 1 pig metal with only a 

 trace of sulphur, instead of No. 4 pig, containing a very large 

 proportion of that objectionable ingredient. The coke now 

 brought before them had been produced in the horizontal coke 

 oven, commonly used in South Wales, but he thought that u 

 still denser quality would be produced in vertical retorts of the 

 Appold type, and in making his designs for the Landore Com- 

 pany, this had been the form of coke-oven he , had specified ; 



