B L A 



B L A 



B, the top of the bodies, 1 2 feet in diameter. 



C, an inferior diameter of 10 feet, previous to the forma- 

 tion of the throat at A. 



D, the top of the fecond row of bodies, c»f tha fame dia- 

 meter as B. 



E, the furnace mouth, or termination of the fecond cone, 

 four fec-t diameter, and proportioned to A. 



F, funnel top for carrying off the flame occafioned by the 

 bJail, fo as not to interfere with the workmen in filling the 

 furnace. 



The dimenfions, as to height, are as follow : 



From B to C height .... - 12 feet 



C to A ditto 6 



A to D ditto ..... 6 



D to E ditto - - - . . 13 



Height of the hearth, and firil row of bofhings, 

 not fliewn in the figure, but being the fame 

 as^g. 1, Plate IX. meafure - - 15' 



Height of the bottom floncs, packing, and 



falfe bottoms. . - - . - ' 4 



Total height of this furnace from the foundation 56 feet 



GG, fire brick lining. 



hh, fpace left for packing. 



II, the common building either of fand-llone, or of 

 bricks. 



Fig. 2. plan and feftipn of the fame furnace taken acrofs 

 the bofhes at B. 



A AAA, fquare of the common building 29 feet upon the 

 fide, bound by BBBBBBBB, eight cad-iron binders ; the 

 number or fetts of thefe requifite, being proportioned, both 

 in llrength and dimenfions, to the height of the furnace. In 

 common, a full binder is applied every fix feet in the 

 height. 



The concentric circles reprefent the various diameters of 

 the interior of the furnace, and aieconnefted each by dotted 

 lines, with their refpcftivc places in the elevation. 



The reafoning which we believe led to the conftruiElion of 

 this furnace, proceeded from a firm behcf that the boihes and 

 throat or fquare of a blalt-furnace were of the greateH im- 

 portance on two accounts. Firit, becaufe they fupported 

 the weiglit of the materials ; and fecondly, becaufe they con- 

 centrated the heat. Thefe acting conjointly, permitted the 

 leaft pofiible quantity of materials to pafs, till they dropt 

 away in a Hate of femi-fufion, or complete feparation. In 

 furnaces, however, the cones of which were 30 feet high and 

 upwards, this v.'as conceived impoffihle to take place for any 

 length of time, to any conliderablc extent. The height and 

 gravitating prell'ure of the materials were more than fufficient 

 to counteract the mod favourable conllruftion of bofhes ; and 

 as this could not admit of diminution, the fufpenfion of the 

 materials, and the concentration of the heat mull be <?fleded 

 by fome other means. This, at one time, was believed to 

 have been completely effefted by the fcheme of an additional 

 fquare, and an extra fet of bolhes ; and there is little doubt 

 but that, by converting perpendicular to lateral preffure, the 

 fufpenfion of the materials was reduced at leall to one half 

 of its former intcnfity. 



It was not doubted but that the procefs of fmelting and 

 feparation would commence, in part, at A ; that what ef. 

 caped fulion and feparation in that quarter, would he eafily 

 refolved below ; and that the procefs of combullion intenfely 

 at work in two different places at once, would greatly facili. 

 tate the general reduflion, and add greatly to the produce in 

 iron of the furnace. Thefe fangulne cxpeftalions were un- 

 fortunately never realized, the folitary inllance of one fnr- 

 mace only being conftruiled in defence of this theory, and 



tKat only for a very temporary endurance, is the bed proof of 

 the inutility of the plan. 



Fig. 3. is the elevated fefb'on of a blaft-furnace, of which 

 feveral were built, and from which it was at one time con- 

 ceived that the greateft advantages were derived. The nume. 

 rous minute gradations of diameter exhibited in the con. 

 flruftion of this furnace, were at one time held in high e(li. 

 mation- by many iron-makers ; and a plan of the prefent 

 furnace circulated from the domains of the lucky projcflor, 

 with as much care and confcioufnefs of rich acquifition, as 

 an antiquary would remove from Hercuh-ineum or Egypt, 

 the precious remains of antiquated obfcurity. 



It will be extremely eafy to trace to its fource this par- 

 ticular bias to form, fo univerfally beheved in at one time, 

 but now configned to that oblivion which experience has 

 taught us it defervcd at a much earlier period. 



It often happens, that when repairing or re-lining a blafl- 

 furnace, the manufafturer avails himfelf of the time thus ob- 

 tained, to overhaul and repair his engine ajid blowing ma- 

 chine. The former movements of the machinei^ may have 

 difcovered to him many errors both in movement and con- 

 ftruAion, which the contlant requifite motion rendered im- 

 practicable for him fooner to remove. In this way, con- 

 fiderablc improvements on the engine and blowing apparatus 

 are frequently made ; and when again in motion, may, by 

 increafing the length and number of the tlrokes in a given 

 time, or by conferring a higher additional working power 

 on the ilcani pifton, increafe at the fame time both the volume 

 and denfity of the blaft. If the produce of the furnace is 

 increafed, which it is highly probable will be the cafe, then 

 the fuperior effects are attributed to a few unimportant cir. 

 cles and lines added to the interior of the cone, the acute- 

 nefs and proportion of which do not furvive the blowing of 

 the furnace three days. 



In like manner, if a work entirely new, commence opera- 

 tions with a greater advantage of blowing power, and with 

 fomething original in the fhape of the furnace, the confe- 

 quent effeflsol the former are indullrioufly attributed to the 

 fortunate conllruftion of the latter, and the grand effential 

 blafl is entirely overlooked,^and its next important alfociates 

 coal and iron-ftone. 



The dimenfions of the prefent furnacfi are as follow : 



Diameter of the cone at A ... 3 feet 



ditto at B . - - ' 4 



ditto at C . . . 8| 



ditto at D . . . 5X 



ditto at E . - - 10 



ditto at F - - - II 



ditto at G - - - 10 



From G to F, the diflance in height raeafures 1 foct 



Increafe of diameter . i foot 



F to E, the diilance is - - 12 



Diminution of diameter . 1 foot 

 E to D, the diltance is - . i J 



Diminution of diameter 6 inches 



D to C, the diftance is - - 6 



Diminution of diameter - i foot 

 C to B, the dillance is - . 2 



Diminution of diameter . 4J 

 B to A, the dillance is ■ . 4^ 



Diminution of diameter . i 

 Height of the hearth and bolhes not rcpre- 



fentcd in the plate - - - J* 



Total height of the cavity of the furnace 



or place occupied by the materials - 40 feet 



The former defcriptious will fuffice and apply to this 



plate. 



