ON FURNACES. 405 



The PRESIDENT : As Mr. Hackney was rather limited in time 

 before luncheon, I will now call upon him to add anything he 

 may desire, or to explain any of the models which were not up here 

 before. 



Air. HACKNEY : I have nothing to add formally to the paper which 

 was read before the adjournment, but I will say a word or two on some 

 of the models which have been brought up since. There is, for instance, 

 a model somewhat old-fashioned of a blast furnace, showing the hearth 

 and the form of the stack. Here, also, is an interesting diagram, showing 

 the increase in the size of blast furnaces. The first one is about fifty 

 feet high, and had a capacity of 5076 cubic feet, and in it about twenty- 

 nine-hundredweight of coke was consumed per ton of iron produced. 

 By increasing the size to a height of eighty feet, and the capacity to 

 from 12,000 to 30,000 cubic feet, the consumption of coke has been marvel- 

 lously reduced viz., from twenty-nine or thirty-hundredweight to about 

 twenty-two-hundredweight per ton, the other conditions remaining the 

 same. There is a model and also a large diagram of the Regenerator gas 

 furnace, which was mentioned in the paper. In the diagram the arrange- 

 ments are shown all on one plan, in order to make the action clear. Then 

 there is another model of Mr. Head's furnace, an ordinary furnace, work- 

 ing with coal, in which the air is supplied by a steam jet. The whole 

 of the arrangements are of cast-iron. In this model a regenerating 

 gas furnace is shown as the work is actually arranged in practice ; the 

 regenerators being under the furnace ; and the reversing valves and 

 flues, which are shown on the diagram below the furnace, are placed 

 at the back. It is really on the principle as the hot-blast stove, 

 which was first introduced, and the application of it to blast furnaces 

 came afterwards. In fact, there are four hot-blast stoves on a small 

 scale under each furnace. Here again is a model of the coal-dust 

 furnace of Mr. Crampton, as applied to puddling. In this furnace 

 there is a chamber lined with oxide of iron, open at one end and 

 enclosed at the other ; it has a removable flue piece, by means of 

 which the charge is introduced and withdrawn. In actual work, as I 

 explained before, the jet of coal-dust and air is blown in at the centre 

 of the flue piece, and the flame passing to the chimney escapes round 

 the jet, and so goes to the chimney. 



