TRANSACTIONS OF THE SECTIONS. 165 



any material. If, for example, a mass of material is to be heated to a temperature 

 of 2000° by flame of a temperature of 3000°, it is plain that the heating gases must, 

 in the ordinary furnaces, escape at a temperature equal to that of the material, and 

 thus carry off with them a heat which will, when the maximum temperature is 

 attained, amount to two-thirds of the whole heat and combustion. The regenera- 

 tive furnace arrests a large proportion of this fugitive heat, and adds it to the 

 gaseous fuel which supports the combustion of the furnace. Wastefulness must 

 always be deprecated in mechanical processes ; but considering how much the gTeat- 

 ness of this country is dependent upon her resources of mineral fuel, and with what 

 prodigality we are now drawing upon these resources, any wholesale wastefulness 

 demands especial reprobation, and renders the introduction of more economical 

 methods of consumption a matter of national importance. The regenerative gas- 

 furnace not only prevents waste of fuel, but it also prevents smoke. Smoke may 

 be altogether prevented, and is in fact inexcusable in the case of ordinary steam- 

 boiler furnaces ; but I know of no means yet introduced by which its prevention 

 can be effected in manufacturing furnaces heated directly by coal. It' gas were 

 substituted for coal, and the regenerative principle applied, the nuisance and dis- 

 figurement occasioned by smoke would be entirely avoided in nearly all manufac- 

 turing processes. But the introduction of gas-fumaces upon so large a scale must 

 necessarily be a work of considerable time, and the system itself would probably 

 require improvement and development to render it so widely available. 



1 might extend my observations to the subjects -of other papers to be read before 

 you, all of which possess considerable interest; but I feel that little would be 

 gained by such an extension of my comments, and that it is better for us at once 

 to proceed to the proper business of the Section. 



On Cham-testing Machines. By Sir "VY. G. Armstrong, F.R.S. 

 The machines referred to were constructed for the Mersey Harbour Trustees. 

 The most important consideration in the construction of a chain-testing machine 

 was to obtain an accurate indication of the strain upon the chain. The hydraulic 

 press had been the means employed of exerting the strain, but the method for 

 determining the amount of strain had been extremely imperfect. Most commonly, 

 the strain had been estimated by the indications on a mitred valve pressed down 

 by a lever and weight. This mode of indication he considered was highly delu- 

 sive, and he pointed out the advantages of substituting a packed loaded plunger 

 for the loaded valve. The packing should consist of cup leather, so that the 

 friction should vary directly as the pressure. When a chain broke in the test, it was 

 desirable to show not only tha± it failed to bear the full test strain, but also the 

 amount of strain exerted at the moment of- fracture. The pendulum indicator has 

 now been brought into general use. In this the pressure upon the plunger is 

 exhibited by the motion of a pendulum through a graduated arc. When a chain 

 broke, the pendulum fell back until stopped by a ratchet, but left a marker at the 

 exact point on the scale attained by the pendulum. Having spoken of the effect 

 of friction on the results indicated, the author proceeded to say that in the arrange- 

 ment of a public chain-testing establishment it was desirable that the apparatus 

 for the various operations should be placed in such succession as would allow the 

 chains to move from process to process without any retrogression. The Birkenhead 

 establishment was then described, in which the machines are adapted to cable 

 lengths of fifteen fathoms, the Board of Trade having recently fixed upon that 

 length as the limit of chain to be tested at one time. He thought the restriction 

 very desirable, and referred to many objections to testing chains in greater lengths. 



On the Manufacture of Cast Steel, its Progress, and Employment as a Sub- 

 stitute for Wrought Iron. By Henry Bessemer. 



On the 13th of August, 1856, the author had the honour of reading a paper before 

 the Mechanical Section of the British Association at Cheltenham. This paper, 

 entitled " The Manufacture of Malleable Iron and Steel without Fuel," was the first 

 account that appeared shadowing forth the important manufacture now generally 

 known as the Bessemer process. 



