384 TRANSACTIONS OF THE 



streams of knowledge we derive most interesting views of the progress of 

 art and industry. We extract the following on iron, far more important 

 than all the gold of the world : 



The 21st ordinary meeting of the one hundred and fourth session, Sir 

 Thomas Phillips, member of the council, in the chair. 



Charles Sanderson introduced the subject of iron. 



Metallurgy is a science of vast extent in its application. In England 

 the application of science to it has been so successful that our iron works 

 now stand models of intelligence and ingenuity, marked by the diligent re- 

 searches of men of high capacity, whose united efforts have produced the 

 comparatively perfect system we now employ. 



The immense iron establishments of England stand pre-eminent both in 

 mechanical skill and practical management. It is in the immense labora- 

 tory of the blast furnace that the first result comes — pig iron, as pure as 

 possible. When chemical analysis has given the quantity and quality of 

 the earthy contents of the ore, other substances are added in such propor- 

 tions as will secure a perfect vitrification of the ivhole. These other sub- 

 stances are called fluxes. The iron ore is charged into the furnace as a 

 calcined peroxide. Limestone is added as a flux to unite with the earthy 

 matter which the ore and \\\.<i fuel may contain. During five or six feet of 

 their descent in the furnace the moisture is expelled, the ore becomes then 

 gradually heated to redness and is prepared for reduction in the^rs^ zone 

 of the furnace. Here the ore loses a portion of its oxide, and becomes 

 reduced to a protoxide. They now enter the second zone, which ends at 

 the boshes or widest part of the furnace. At this point the ores are not only 

 completely deoxidized, but become partially cemented. The limestone 

 has now parted with its carbonic acid and the alkaline part of it unites with 

 the earthy matter, together forming slag. The whole now gradually but 

 slowly descends through this part of the furnace which is made wider in 

 order that the materials may take a longer time in passing through this 

 space, thus leaving them for a longer time subjected to the action of the 

 carbon. The metallic portion becomes gradually developed and acted upon 

 by the carbon of the fuel, and the highly carbonizing gases it meets with 

 in the lower region of the furnace. It then passes the direct action of the 

 blast at the tuyers and falling into the dam, separates itself by its superior 

 specific gravity from the vitreous earthy matter which covers it and pro- 

 tects it from the oxidizing influence of the blast. The air blown into the 

 furnace is composed, in round numbers, of 79 nitrogen and 21 oxygen. 

 Before this air has risen three feet from the tuyere it is converted into 65 

 nitrogen and 27 carbonic oxide, &c. 



Sir Francis Knowles proposes to introduce potash, felspar or soda, into 

 the furnace charges. He adds lime equal to two-thirds of the weight of 

 the silica contained in the felspar ; the bases then become lime, alumina, 

 and the alkali, which being in excess, is released to form the cyanide re- 

 quired. He states that his trials have given him a cinder entirely free 

 from iron. 



