14 On the Materials ufed 



manufacturers *. If the woods receive neceflary care and 

 attention after the firft cutting, they will replace themfejves 

 at periods from 15 to 18 years. The charcoal ufed in 

 Siberia is all made from the pine and larch, the country af- 

 fording no other varieties of timber. In Sweden the ma- 

 nufacturers are fupplied with a confiderable proportion of 

 harder woods, which is greatly in favour of the manufacture. 



It has been already noticed, in a former paper, that the 

 fuel ufed in Britain at an early period, and fo far down as 

 the beginning of the prefent century, chiefly confifted of 

 wood. The kinds of wood ufed for this purpofe were 

 various ; but char of hard wood, fuch as oak, birch, aui, 

 &c. &c. was- always preferred to that made from pine, hollv, 

 fallow, &c. &c. At the fmall remaining number of char- 

 coal furnaces now in this country, the oak has ftill the un- 

 doubted preference. Its firmnefs and continuity enable it 

 in the blaft furnace to f;pport and convey principle to the 

 iron contained in a larger portion of ore, than charcoal 

 made from fofter wood. The fame properties alfo enable it 

 for a time to fuftain a heavier prefTure of air from the dif- 

 charging pipe : this facilitates the reduction of the whole, 

 and greatly augments the weekly produce in iron. The 

 mode of preparing charcoal of wood for the bl aft- furnace, 

 though extremely Ample, is yet capable of being greatly 

 nnfunderftood, fo as to occafion a confiderable wafte of 

 wood in the procefs. The following is the detail of an 

 operation which I have feen fuccefsfully tried, and which 

 was productive of excellent charcoal. It is the fame I 

 believe as is followed at the two charcoal furnaces in 

 Argylefhire. 



Firll of all, a plot of ground is raifeu a little higher than 



* In Sweden there s 3 law reftrifting the manufacturers of iron to a 

 certain annual produce ; and this quantity is always in proportion to the 

 ground attached to the work. In this manner the wool is enabled to 

 replace itfelf at certain intervals ; and each work is inflated of an annual 

 though moderate fupply. The more extenfive and unpeopled tvacls of Sibe« 

 ria, render fuch exactitude in the execution of the laws lefs ccceifary. 



the 



