for Manufacturing Cajl Iron. I - 



the unrounding furface : this is made (lightly convex. The 

 burner commences by placing in the centre a circle of 

 flicks, tranfverfely inclining, and crofling each other near 

 their tops. Around thefe are built fucceffive circles of wood 

 of various fizes, from i to 10 inches diameter; but care is 

 always taken to place thofe of fimilar diameters in the fame 

 circle. A round of beams, of the largeft nature, is immedi- 

 ately followed by one fo much fmaller as to fill up the in- 

 terfticcs between thelarger diameters, that no more air may 

 be admitted than is neceflary to excite gradual combuftion. 

 Thefe are again followed by pieces of an increafing diameter. 

 This mode of ranging the large and final] fizes is continued 

 till fuch time as the pile is deemed fufficien»ly large. The 

 total width may then meafure from 20 to 30 feet-. The late 

 layer is commonly compofed of fmall brufli-wood. The 

 whole is then covered with turf, the grafly fide towards the 

 wood ; a coating of earth is then applied all round the 

 bottom of the pile, and firmly beat to prevent the unnecef- 

 fery admiffion of air. A fmall funnel, or opening on the 

 t»p, is preferved by the tranfverfe pofuion of the firft layer 

 of wood; this is generally about 18 inches deep, into which 

 the burning fuel is introduced. Combuftion is in thfs 

 manner firft conveyed to the top of the pile, and is continued 

 by feeding the fmall craters with pieces of wood for 4 or 5 

 days. When the interior part of the fire next the too is 

 deemed fumcicntly kindled and fpread over the whole 

 diameter, a row of holes is opened a few inches below, each 

 about two inches diameter. The hole at the top is then 

 entirely fhut up, and the fire, now completely fpread, flowly 

 defcends to where the air is admitted by means of the fmali 

 apertures. When this is obferved by the burner, which is 

 known by the difappearance of fmoke and vapour, they are 

 immediately fhut up, and a fecond row opened 6 or 8 inches 

 under the firft. In this manner the fire is conduced to the 

 foundation of the pile, and the whole mafs expofed to pro- 

 per combuftion. The intention of the operation is to brinfc 

 the whole pile to a ftatc of complete ignition, but in fuch a 



planner 



