The audience received me very kindly, and I had the honour of reading my paper, of which a verbatim copy is here given.

The manufacture of iron in this country has attained such an important position that any improvement in this branch of our national industry cannot fail to be a source of general interest, and will, I trust, be sufficient excuse for the present brief, and, I fear, imperfect paper. I may mention that for the last two years my attention has been almost exclusively directed to the manufacture of malleable iron and steel, in which, however, I had made but little progress until within the last eight or nine months. The constant pulling down and rebuilding of furnaces, and the toil of daily experiments with large charges of iron, had already begun to exhaust my stock of patience; but the numerous observations I had made during this very unpromising period all tended to confirm an entirely new view of the subject which, at that time, forced itself upon my attention, viz., that I could produce a much more intense heat without any furnace or fuel than could be obtained by either of the modifications I had used, and consequently that I should not only avoid the injurious action of mineral fuel on the iron under operation, but I should at the same time avoid also the expense of fuel.

Some preliminary trials were made on from 10 lb. to 20 lb.of iron, and although the process was fraught with considerable difficulty, it exhibited such unmistakable signs of success as to induce me at once to put up an apparatus capable of converting about 7 cwt. of crude pig iron into malleable iron in thirty minutes. With such masses of metal to operate on, the difficulties which beset the small laboratory experiments of 10 lb. entirely disappeared. On this new field of inquiry I set out with the assumption that crude iron contains about 5 per cent. of carbon; that carbon cannot exist at a white heat in the presence of oxygen without uniting therewith and producing combustion; that such combustion would proceed with a rapidity dependent on the amount of surface of carbon exposed; and, lastly, that the temperature which the metal would acquire would be also dependent on the rapidity with which the oxygen and carbon were made to combine; and consequently that it was only necessary to bring together the oxygen and carbon in such a manner that a vast surface should be exposed to their mutual action, in order to produce a temperature hitherto unattainable in our largest furnaces.

With a view of testing practically this theory, I constructed a cylindrical vessel 3 ft. in diameter, and 5 ft. in height, somewhat like an ordinary cupola furnace. The interior of this vessel is lined with firebricks, and at about 2 in. from the bottom of it, I insert five tuyére pipes, the nozzles of which are formed of well-burned fireclay, the orifice of each tuyére being about 3/8 in. in diameter; they are so put into the brick lining (from the outer side) as to admit of their removal and renewal in a few minutes when they are worn out. At one side of the vessel, about half-way up from the bottom, there is a hole made for running-in the crude metal, and on the opposite side there is a tap-hole stopped with loam, by means of which the iron is run out at the end of the process. In practice this converting vessel may be made of any convenient size, but I prefer that it should not hold less than one, or more than five, tons of fluid iron at each charge. The vessel should be placed so near to the discharge hole of the blast furnace as to allow the iron to flow along a gutter into it; a small blast cylinder will be required capable of compressing air to about 8 lb. or 10 lb. to the square inch. A communication having been made between it and the tuyéres before named, the converting vessel will be in a condition to commence work; it will, however, on the occasion of its being used after re-lining with firebricks, be necessary to make a fire in the interior with a few bucketfuls of coke, so as to dry the brickwork and heat up the vessel for the first operation, after which the fire is to be all carefully raked out at the tapping hole, which is again to be made good with loam. The vessel will then be in readiness to commence work, and may be so continued without any use of fuel until the brick lining in the course of time becomes worn away and a new lining is required.

I have before mentoned that the tuyéres are situated close to the bottom of the vessel; the fluid metal will therefore rise some 18 in. or 2 ft. above them. It is therefore necessary, in order to prevent the metal from entering the tuyére holes, to turn on the blast before allowing the fluid crude iron to run into the vessel from the blast furnace. This having been done, and the fluid iron run in, a rapid boiling-up of the metal will be heard going on within the vessel, the metal being tossed violently about and clashed from side to side, shaking the vessel by the force with which it moves. From the throat of the converting