I oxide of iron, to lute it down and exclude the air . The pots A paper recently read before the Franklin Institute of are then put into the furnace until it i � full, and the whole Philadelphia, by Mr. T. S. Speakman, representative of the brought up to a cherry red heat, or a httle beyond. About Institute at the VieLma Exposition, gives the following in-eight hours are necessary for its perfect saturation by the teresting details of the manufacture of tin plate as carried on heat. When

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... from the furnace, they are slowly in Wales: cooled in a place free from draft, and then the pots are In the opinion of Mr. Henry I. Madge , tin plate manufac-opened. The plates never lie perfectly flat, and should be turer, of Swanselt, in Wales, from whom I received the fol-of a dark straw color at the edges. If the air should get in lowing information, the manufacturer prefers making his in small quantities, a deep blue color will cover the sheets own iron to purchasing it, because he can thereby insure a more or less. The plates adhere slightly, are again separat more equable quality; he therefore buys suitable pig iron. ed, and ready for the second pickling room. The plates are For common coke tin plvtes, the "iron bars" are made then submitted to a hot but more dilute pickle of sulphuric from puddled iron. The puddled ball is sometimes squeezed acid, and again chemically cleansed; taken from the acid and sometimes hammered; much depends on the care of the bath, they are well washed in running water, and kept in puddler to so bring forward his ball that all its parts shall clean water until the tinman is ready for them. be equally decarbonized, when the fracture will be of a uni- The tin man takes the plates from the water bath (where form , dull gray color, without crnde admixtures of bright they lie some hours) and plunges them wet into a bath of crystals. The unreduced crystals produce" wasters" of the hot palm oil, called the " grease pot." When they have ac iron plates; and if any such escap'l the notice of the mill qui red the temperature of the grease pot, they are removed manager, the wasters are thrown aside again after being with tongs and quickly submerged in a bath of tin. The covered with tin. If they escape the eye of the" assorier," oil mIXed with the water from the plates floats at the top, the tin plate worker will find them fracture across the forming a flux which covers the melted tin and prevents ox angles or bends of the sheets in working them up. The idation. With the tongs , the sheets or plates are continual puddled ball, produced under the best conditions, is then ly kept moving and separated, to insure the tin getting be taken to the" shingler, " who submits it to the squeezer or tween all of the sheets. When the bath has recovered its hammer, sometimes both. This operation should be care-heat, which it generally does in about half an hour, the tin fully executed. As the puddled ball is ' rugged and full of man examines the charge, and if he finds that perfect amal cinder, the cinder has to be squeezed out by this operation, gamation has taken place between the two metals , he reo and at the same time the roughness must be so managed as to moves them with a tongs to the next bath, which is kept at a be wrolded into a solid (!ompact mass, which cannot be so low temperature. well done in after operations. Some say it cannot be done The temperature, raised by the change from the" tin pot," afterwards, as the whole mass f;an never again be is again all owed to cool down to a few degrees over the melt brought up to a thorough welding heat throughout, unless at ing point of the tin, when the plates are taken in lots of a the expense of much waste and loss. The bloom from the dozen or two at a time, and laid on an iron slab, which is at " shingler " is at once passed through the rolls , or roughed the side or head of the pot. The waste metal and grease run down to No.1 bar. Some prefer letting the blooms lie ex-back into the pot, the slab being inclined. The workman posed to the action of the elements for a time, ancl others then takes up sheet by shept with the tongs, and dips each think it of no importance. The bar, while hot, is cut into into another bath of fine Detal, kept at a heat little over lengths and piled, five pieces being put and heated together melting point. immediately withdraws it, and places it in a in the" balling " or reheating furnace. When the faces are rack immersed in a large pot of melted palm oil kept at the brought up t� a welding heat, and the whole mass softened, proper temperature, where they are allowed to remain a cer it is again taken to the hammer, some rolling at once, others tain time. The sheets are then slowly lIfted out of the . returning the bloom into the furnace to again bring up the grease by a boy, who separates them into proper lots by heat. It is then rolled out into the fiuished bar, of suitable counting carefully, regulating the intervals of time between size and thickness for the kind of plates required. them. The grease recoils from the top plate; and as little