TRANSACTIONS OF THE SECTIONS. 211 



hodih/, and placed iu the machine, which reduces it at one operation to the required 

 size and shape. The rolls of the machine ai-e geared together so as to rotate iu the 

 ■same direction ; the iron is placed between the worlring rolls, which are brought to 

 bear upon the bar hj po^Yerful screws gradually pressing the rolls nearer together 

 and reducing the bar to tlie required dimensions. The part of the rolls which fomi 

 the tom-nals press upon the bar, reduciaig its diameter at that point, afterward bear- 

 ing upon the middle of the bar, and by degrees along its whole length. As the bar 

 becomes reduced in diameter it becomes extended in length 14 to 18 inches ; to 

 allow for this elongation, those parts of the rolls which form the tournals are ar- 

 ranged to slide laterally with the axle, while the rolls are screwed closer together 

 until the finished axle is produced, and which, by the greater uniformity of the 

 Tolling pressure, gives the direction to the fibre best calculated to increase the 

 strength of the axle. 



Hydraulic Machinery for Steering, Slopping, and Working Heavy Steam- 

 engines discharging Cargo. By Andrew Betts BROA^if. 



The chief feature of novelty in the invention, as set forth in this paper, is in an 

 apparatus called a "steam-accumulator," by which a reservoir of water at a pres- 

 sure of 1000 lbs. per square inch and upwards is obtained on board ship. Having 

 this pressure, a steering-gear of light construction and great power is made use of 

 possessing certain relief valves, or other expedients b}' which perfect elasticity in 

 the rudder may be obtained. 



In a similar manner, by the use of hydraulic cylinders and rams, the same pump- 

 ing-machineiy and "steam-accumulator" which works the rudder at sea is made 

 available in port for the discharge of a ship's cargo, as well as, on entering a port, 

 to start, stop, and reverse heavy marine engines. 



On Appliances for the production of Heavy Forging. 

 By Lieut. -Colonel Clay. 



On the Purification of Public Thoroug?ifares. By "W. J. Cooper. 

 [For an abstract of this paper see Section B, page 53.] 



On the Efficiency of Furnaces and Mechanical Firing. 

 By George F. Deacon, G.E. 



In opening this subject, the author refen-ed to one of the veiy numerous expe- 

 riments of the late Mr. C. Wye Williams, in which air was admitted to the vola- 

 tile products of combustion of the carbon through holes in an arched plate, divid- 

 ing the fuel from end to end of the furnace. 5lr. WiUiams firmly believed that 

 such a system was capable of producing perfect combustion, and he strenuously 

 opposed the idea that any advantage was to be gained by making use of air for the 

 combustion of the inflammable gases which had been raised m temperature by 

 heat abstracted from the furnace in which they were produced. The well-known 

 experiments of Professor Tyndall and Dr. Frankland, by which it was clearly shown 

 that, owing to the gi-eater inability of the atoms of rarefied air, the energy of 

 combustion was mthin wide limits independent of the density of the air, went far 

 to overturn the arguments with which Mr. Williams upheld his opinions. 



Arrangements similar in form to the perforated arched plate had been tried by 

 the author ; but in a series of careful experiments on a large scale only those which 

 had included means for heating the inflowing air had been foimd efficient in pro- 

 ducing perfect combustion of the gases. Transverse arched bars 7 or 8 inches 

 high, presenting to the rising air extensive heating-surfaces, had been substituted 

 for the bent plate, the heat for raising the temperature of the air having been ob- 

 tained, both by radiation and conduction, from the incandescent fuel. 



14* 



