president's address — SECTION B. 67 



introduction of the molten metal and for the escape of the gases, sparks, 

 etc. The chemical action going on within is attributed to the decar- 

 burisation of the pig iron, the temperature evolved being due to the 

 combustion of a part of the carbon. Subsequent patents, extending 

 through 1856, recognise further features of the process, which we do 

 not need to go into. Suffice it to say that the fertile facility of the 

 inventor in a few years wholly exhausted the budget of possible me- 

 chanical variations of apparatus which could be made use of, and was 

 not long in finding the type which has since permanently established 

 itself in iron practice. This is the laterally suspended, tiltable, pear- 

 shaped converter, with vertical bottom tuyeres, which dates from 

 1858. There is no doubt that this tilting movement has very largely 

 contributed to the utility, as well as renown, of both the apparatus 

 and the process. It is, however, not original, nor is this the first time 

 that Bessemer availed himself of it — vide his prior use of it — for heating 

 and melting apparatus in the manufacture of bronze powder and of 

 optical glass (d). The mechanical movement is doubtless of an ancient 

 date, applied to household utensils among other things. A pertinent 

 metallurgical precedent may be seen in the tilting cupola furnaces, 

 himg on trunnions and moved by a lever, which, at Bessemer's time, 

 were still in use in Sweden for the melting down of cast iron for foundry 

 purposes ; size 8ft. high, with two tuyeres and a taphole in the same 

 level, a little below the line of suspension (e). Bessemer adapted the 

 general mechanical idea to his specific wants, adding the hollow trunnion 

 and the wind box for the supply of the blast, and the geared movement, 

 which he first actuated by a hand crank, later by means of the well- 

 known hydraulic apparatus. 



Of special interest is the form of 1862, which is the prototj'^je of 

 our customary upright copper-converting vessel, with raised side tuyeres 

 entering the body horizontally a certain distance above the bottom, 

 and which will be referred to again later on. 



Chemically, progress was much less rapid, and, from an ultimate 

 point of view, we are far behindhand in this respect even to-day. In 

 the absence of a proper understanding of the chemical features, pressure 

 and temperature seemed to the inventor the principal essentials, and 

 he hoped, with adequate pressure and a suitably constructed vessel, 

 having an almost closed opening, to attain temperatures of up to 

 50,000° F. This aspect of the process owes much to SAvedish engi- 

 neers, who, while neglectful of the mechanical side (as is evidenced by 

 their retention of the old fixed vessel of 1855-6), were a mainstay of 

 the chemical principles of the method during its years of depression, 

 when it failed on the impure English ores. Bessemer owes immensely 

 to Goranson and others, who perfected the pneumatic side by properly 

 appreciating its superior importance (/). They increased the tuyere 

 -area, thus obtaining a more abundant air supply, with a corresponding 



(d) Sir Henry Bessemer, F.R.S., " An Autobiography," 1905, pp. 71, 105. 

 (e) See, for instance, Wehrle, " Probier-u. Hiittenkunde," 2nd ed., 1844, plate 6, 



figg. 165-0. 

 (/) Harbord, Steel, 1904. 



