MECHANICS AND USEFUL ARTS. 57 



are fused, and become incorporated with the previously enamelled 

 surface. 



IMPROVED APPLIANCES FOR THE PRODUCTION OF HEAVY 



FORGINGS. 



The forging of iron in large masses is a subject of so much 

 importance to our engineering industry that it needs little apology 

 for its introduction to the mechanical section of the British Asso- 

 ciation, and any improvement in the machinery or appliances for 

 the more economical or rapid manufacture of large masses of 

 wrought iron, or for any improvement in quality, must be of great 

 interest to all manufacturers where such products are needed. 



These improvements, in the manufacture of large forgings, I 

 intend to class under 3 heads. I propose simply to mention a 

 few. prominent facts very briefly, but shall be glad to answer 

 any inquiries that members may require further information 

 about. 1. Improved heating by Siemens' regenerative gas fur- 

 nace. 2. Facilities for handling and moving large masses of 

 wrought iron from the furnace to the hammer, and for moving 

 them under the hammer. 3. Improved hammers, with a clean, 

 unfettered fall, and with such width of standards as to give the 

 workman all the comfort and convenience possible in executing 

 the necessary operations of shaping, forging, and cutting the 

 material to the required form. 



1st. Improved heating by Siemens' regenerative gas furnace. 

 It is generally admitted that iron in large masses is greatly dete- 

 riorated by long exposure to high temperatures, and that a crys- 

 talline structure is developed in consequence of such a form and 

 nature as to detract in a very great degree from the strength of 

 the material. It must, therefore, be admitted that furnaces, such 

 as those of Siemens, which produce the most intense heat in the 

 shortest possible time, must cause less deterioration to the product 

 in hand than those which are slower in operation ; but a more im- 

 portant item in this consideration is that the facilities given for 

 regulating the admission of gas and air in a neutral flame can be 

 produced ; and, in consequence, the iron may be preserved from 

 that burning and oxidation which are the cause of the formation 

 of those large facets or crystals which weaken many wrought- 

 iron structures of large size to such an immense extent. 



Another improvement, from these furnaces where the iron is 

 prepared from the pig, is, that the gas furnaces do not bring over 

 the large amounts of unconsumed ash or debris from the coal 

 which is usually deposited on the body of the iron made in the 

 ordinary puddling furnace, and, in consequence, the iron is more 

 free from those specks and flaws which are so observable in or- 

 dinary iron, and which produce the heating and galling so com- 

 mon in large forgings, as heretofore made, and which cause the 

 chief torment of the practical marine engineer. 



Perhaps the greatest advantage which the Siemens' furnace 

 offers is in the manufacture of forgings of puddled steel, from the 

 facility in which the flame of the furnace may be regulated, first, 



