26 PEELIMINABY NOTICE ON THE 



an important influence on the results of any smelting processes 

 undertaken. 



These are only a few of the questions which bear very materially on 

 the full and accurate investigation of such subjects, and for the solution 

 of which we have as yet no data in this country.* 



Any estimate therefore that can be now made, as to the amount 



Onlyan approximative °f charcoal required for such manufactures as 

 es ima e la possi e. ^^ have Contemplated, can only be considered 



approximative. 



We may assume, I think, that the heating power or calorific 

 Heating power of char- "'^^^^ of charcoal, is slightly superior to that of 

 the best quality of coke, and from 3 to 5 per cent, 

 superior to that of good coal.-f- 



We shall be scarcely safe therefore in estimating for a smaller quan- 

 tity of charcoal per ton of ore used than would be required of coal. 



* I confidently hope that as Soon as the establishment of the Museum of Practical Geology, 

 recently sanctioned by the Supreme Government of this country, shall be fairly organised, 

 we shall be able to remove the doubt which hangs over this and other similar subjects, 

 t The following are the results (in brief) of experiments :— 



Bis. 

 1 IB. of Charcoal (average of birch, fir, alder and oak) gave as a mean result 



in IBs. of water raised from to 100 centigrade, ...... ... 72'00 



lib. of Charcoal (average of 11 varieties,) ...... .... 71"90 



1 lb. of French Coal ( „ „ 3 „ ) . . 62-80 



lib. ot Lancashire Coal „ 4 „ .... 64'47 



lib. of Newcastle „ „ 4 „ .. 68-88 



lib. of Welsh „ „ 6 „ 73.34 



lib. of Coke from Durham Coal ... 71.59 



Pure carbon yielding ••... 78-15 



The relative pyrometricaJ heating eifects of the different fuels burnt in contact with air may 

 be thus given in degrees centigrade : — 



Wood - 1575 to 1750 



Wood Charcoal 2100 2450 



Coal (5 per cent, ash) 2200 2350 



Coke (5 per cent, ash) 2350 2450 



PureCaibon 2458 



[Scheera's Metallurgie. 



