406 Analyses of JJoohs. 



at an avoirdupois ounce and a quarter, which is the weight of a cu- 

 bical foot of air at 50° Fahrenheit, these feet correspond precisely 

 with 2 cwt. of air a minute, or six tons an hour. Two tons of solid 

 material an hour, put in at the top of the furnace, can scarce hurtfully 

 affect the temperature of the furnace, at least in the hottest part of it, 

 which must be far down, and where the iron, besides being reduced 

 to the state of metal, is melted, and the slag too produced. When 

 the fuel put in at the top is coal, I have no doubt that, before it comes 

 to this far-down part of the furnace, the place of its useful activity, the 

 coal has been entirely coked ; so that, in regard to the fuel, the new 

 process differs from the old much more in appearance than in essence 

 and reality. But if two tons of solid material an hour, put in at 

 the top, are not likely to affect the temperature of the hottest part 

 of the furnace, can we say the same of six tons of air an hour, 

 forced in at the bottom near that hottest part ? The air supplied is 

 intended, no doubt, and answers to support the combustion; but 

 this beneficial effect is, in the case of the cold blast, incidentally 

 counteracted by the cooling power of six tons of air an hour, or two 

 cwt. a minute, which, when forced in at the ordinary temperature 

 of the air, cannot be conceived otherwise than as a prodigious refri- 

 geratory passing through the hottest part of the fuanace, and re- 

 pressing its temperature. The expedient of previously heating the 

 blast, obviously removes this refrigeratory, leaving the air to act in 

 promoting combustion, without robbing the combustion of any por- 

 tion of the heat it produces." 



From a table appended to this paper, and furnished by Colin Dun- 

 lop, Esq., it appears that in 1829, the average weekly product of 

 the Clyde iron- works was 110 tons, 14 cwt. 2 qrs., and the average 

 of coals used to 1 ton of cast-iron was 8 tons, 1 cwt. 1 qr. with.the cold 

 air; while in 1830, these numbers were respectively, 162 tons, 2 

 cwt., 1 qrs., and 5 tons, 5 cwt. 1 qr. with heated air ; and in 1833, 

 245 tons, and 2 tons, 5 cwt. 1 qr., also with heated air. The fol- 

 lowing table gives the materials constituting the charge in the seve- 

 ral years : 



Material* constituting a Charge : 

 cwt. qrs. lb. 



1829, Coke - - 5 



Roasted Ironstone, 3 1 14 



Limestone, - 3 16 



II. — Travels in the United States of America, Canada, i)Y. By 

 J. Finch, Esq. London : Longman & Co. 



This work derives no small degree of interest from the circum- 



