for cqjiing large Pieces of OrdnancCy 6^c. 247 



PP, fpace of 2 inches for fluffing with fand. 



QQ, conniion brick bulidiiig. ',, 



KR, caft-iron lintels, over which are thrown double 9-inch 

 arches, fo that at any time the inferior buildini^ can be taken 

 down to make repairs, without iLaking or in the leaft injuring 

 the chimney. 



S. The dotted lines liere are meant to reprefent what is 

 called the tapping-hole. When a large piece of goods is to 

 be caft, lifting the metal with ladles would be impra6licrtble. 

 A fliarp-pointed bar is driven up this opening. The iron, 

 then flows freely out into a large bafon of fand niadt for its 

 reception. It is then conducled, by collateral channels, into 

 the mould. 



' The fpace under the curved dotted lipe from G to L, by S, 

 is filled with a mixture of fand and allies. When the fiu- 

 iiace is prepared to melt, the whole of the bottom receives a 

 ftratum of iharp clean fand about two inches thick. Tliis is 

 broken up at night, and frcQi land is fubliituted far it befor<$ 

 the fire is kindled in the morning. 



Fig. 3. is a horizontal feeMion of the chimney or ftalk, takcm 

 where the flues aflume a perpendicular direCLiou. The letters 

 in this figure corrcfpond to thofe in the vertical fc6f ion, fig. 2, 

 The height of the chimney ought nol to be lefs than 45 iwi: 

 if 50 feetj the effect will be fooner and of courle better pro- 

 duced. ., '.,j,v,, ■ . ^■>,:. 7.1 I. i ■• .: 



RemaHi ^^O'n^e Melting ofh-oWin fh^fs Pil^fijices. 



The , cffeA \vilhed tO' bie procUtcea in air-furnace^ ,is the 

 fufion of a certain portion of pig- or call-iron for the purpofe 

 of being poured or run into .moulds to iiuru^ articles ofalnioH 

 every defcription. ;,,,., ,,,,., , ,j , , ,^ ,,„, ,, ..,<, j 



The jKeparaiion prev^oq^fo.njdiing is as follows: — After 

 the bottom of the furnace is laid, and fmoothed with frefh 

 fand, and all the openings made air-tight, the furnace-man 

 iiitroduces a kindling at the teafing-hole, occompanied with 

 new pit-coa,l. In a few minutes a confiderahle volume of 

 dark fjaiwc mixed with fn)oV,e fs produced. The fire qui; kly 

 gathers flrent;tli ; more coal is introiuced; a:id the furnace 

 now bet'kTiie.s filled with a yelU>\v-col')ured flame. Bv C911- 

 tiuuing this operation for an hour, or an hour and a quarter, 

 the furnace and flame Vv'ill have become completeh white j 

 tlie latter (leady, and at limes apparently " ithoul moti'Mi, 

 The furnace-man now judoes the bottom to liavc been fufii- 

 cicntly hardened for reeeiving the pig-iron without any rifk 

 of finking. The charging-d<.)or is now oj)ened, and the pig- 

 njeUl thrown carefully and regulf^rly upon that part of llio 

 i\ 4 bottom 



