B L A 



inferior, an unufual timidity would precede any movement 

 that might have for its objetl the enlargement of the column 

 of air or the increafe of its t'enfity. 



This, however, once done away, there feemed no end to 

 the quantity of air that a coke blaft furnace could with pro- 

 priety receive before any bad confequences enfued. Denfitv, 

 however, was found inimical to quantity, and the fame law 

 was at lad dilcovered to hold good regarding pit coal as 

 with wood, that the fofter qualities could be overblown, 

 while the more denfe and conipaft Ilrata remained undinii- 

 nifhed before a heavier b!a!l. 



The celebrated foundery of Carron was begun about the 

 year 17C0, and as was the cuftom of the times, the opera- 

 tion of blowing was performed by large bellows moved by 

 means of a water wheel. Pit coal was the ftaple fuel iu view, 

 but the fcanty fupply ot air, and its uant of denfity, liJom 

 permitted the produce of the furnace to exceed 10 or 12 tons 

 weekly, and frequently, in fummer, the quantity was re- 

 duced even below this. The company coJlefted irnmenfe 

 quantities ofcliarcoal wood, and lound their blaft ni'ieh bet- 

 ter calculated for the operation of fmclting with it, than the 

 uninflammable pit coal obtained in their neighbourhood. 

 Experience, however, gradually unfolded means of adopting 

 machinery, more calculated to the nature of the coal fuel, 

 more powerful wheels were conftrufted, the bellows was 

 abandoned, and in their place large iron cylinders were in- 

 troduced blowing both up and down. A larger column of 

 air of triple or quadruple denfity was obtained, and tffefts 

 equivalent to thefe great improvenifnts followed at the blaft 

 furnaces. The fame furnaces that formerly yielded 10 and 

 li tons weekly, now fometimes produced 40 tons in the 

 fame fpace, and on the average in one year not lefs than 

 1500 tons of metal. 



Fruni the period {1750 to 1760) that pit coal coke was 

 applied as a fubllitutc tor wood charcoal in the blaft furnace, 

 the iron trade began immediately to revive, and its pro- 

 grefs in England and Wales, in a period of 30 years, was 

 truly aftoniftiuig. The general ufe of pit coal, moft un- 

 queftionably, occafioned an earlier relinquiftiment of many of 

 the charcoal works, than would have otherwife betn the 

 cafe, but the colleftive manutafture had fo much increafed, 

 as to render this an obj. 61 of trifling importance. 



The following is a correft ftatenient of the annual manu- 

 faiflure of pig-iron in England and Wales in the year 178S: 



_ „.,_ ,. Total 



Charcoal Bl.ift Furnaces. 



No. oi" 

 Fuiiiacts. 



Tons at 

 each. 



Gloucefterfhirc 



Monmouthlhire 



Glamorganftiire 



Carmarthenfhire 



Merioneth 



Shropfltire 



Derbyftiire 



Yorkftiire 



Weftmoreland 



Cumberland 



Lancafhire 



Saffex 



4 

 3 



3 



I 



I 



3 

 I 

 I 

 I 

 I 



3 

 2 



650 

 700 

 600 

 400 

 400 

 600 

 300 

 600 

 400 

 300 

 700 

 150 



each 

 County, 



2600 



2100 



1800 



400 



400 



1800 



3 CO 



600 

 400 



300 



2100 

 ?oo 



Total of charcoal furnaces 24 



Average produce from each furnace 

 Former average produce 



13100 



Tons. cwt. qr, 



545 16 2 



294 1 I 

 251 15 I 



BL A 



Increafed produce per furnace, from the year 1750 to 1783, 

 attributable entiiely to the general improvement of machi- 

 nery, and the introduftion of the lleam engine, 251 Ions, 

 15 cwt. I qr. 



About the year 1750 the annnal quantity of 

 charcoal pig-iron manufaftured in England 

 and W?les amounted to - - 



In 17SS the fame wai ... 



Tons. 



I 3 1 oo 



Dccreafe in charcoal iron betwixt i750«nd 1788 4250 



attnbutable chiefly to the decreafe of wood, but 

 part owing to the ufe of pit coal as a fubftitute in the 



Coke Pig Elail Furnaces in 1788. 



No. of 

 Furnaces. 



Shropdiire . - 21 



Staffordftiire - .6 



Derbyfliire - .7 



Yorkftiire . - 6 



Cumberland - . i 



Chtftiire - - i 



Glamorgan ftiire - .6 



Brecknockftiire - - 2 

 Staffordftiire 3 new furnace* expefted 



to blow fame year - 3 



Tins a 

 each. 



1 100 



750 

 600 



750 

 700 

 600 



I too 



800 



alfo in 

 furnace. 



Total in 



each 



County. 



23100 



4500 



4«oo 

 4500 

 700 

 600 

 6600 

 1 600 



800 2400 



•53 



48200 



Total furnaces and coke pig-iron 1 

 manufaftured in 1788 - -J 



An article entirely new, which though not difcovered, was 

 rendered a profitable and highly ufeful manufailure in the 

 lalt 30 years. 



Average produce at each furnace 907 tons. 



TorT5. 

 Total of charcoal iron ... '3 100 



Ditto of coke pig-iron • - 48200 



Total of pig-iron manufaftured in England J , 



and Wales annually - . . f ^'30° 



At the fame period in Scotland there were erefted, and 

 in blaft:, charcoal furnaces in the weft: Highlands, viz. 



No. of Tons 



Goatfield 

 Bunawe - 



Coke pig furnaces, viz. 

 Carron 

 Wilfontown, orCIeugh 



Furnaces. 

 I 



each. 

 700 

 7C0 



4 

 2 



1000 

 8do 



Total. 



700 

 700 



4COO 

 1600 



Total quantity of pig-iron manufac- 7 „ 

 tured in Scotland - - j 



Average produce for each furnace annu- 

 ally 875 tons. 



Total quantity of pig-iron made in 

 England and Wales - 77 



Annual quantity manufaftured imme- 

 mcdiatcly preceding the introduc 

 tion of pit coal for furnace fuel 



Annual incteafe in 30 years 



85 



26 



7000 



61300 

 68300 



17350 

 50950 



The period of 1788 or 1790 may be called a new aera in 



the manufncturing of pig-iron. The double power engine 



of Mr. Watt had now become more general, and was 



4 C 2 ywirly 



