182 Dr Fyfe on the Use of Steam 



and giving I'ise to the formation of carbonic oxide and hydro- 

 gen, these, provided air is freely supplied, are consumed, and, 

 during their union with the oxygen of the air, in their passage 

 up through the furnace, will also give forth heat. 



The only instance on record that I am acquainted with, in 

 Avhich steam was passed through fuel with any definite object 

 in view, is that mentioned by Mr Mushet, of the Clyde Iron- 

 works, in the 6th volume of Tilloch's Magazine. In alluding 

 to the different means of procuring blasts for iron-furnaces, he 

 states, among others, the ivater-vault, by which air is thrown 

 into chests inverted in water, by means of pumping cylinders ; 

 and, in which case, the air is of course loaded with moisture. 

 Though, by this means, a steady cool blast is procured, yet, 

 according to Mr Mushet, there is one objection to its use, 

 viz. the tendency which the air has to take up a considerable 

 poi'tion of moisture, and introduce it into the furnace, by 

 which he seems to dread, if I may be allowed to judge from 

 what occurs in another part of the paper, an intense tempera- 

 ture excited by the action of the moisture ; for he there states, 

 that when a loose blast is surcharged with moisture, the inflam- 

 mation which takes place at the tuyre is prodigious ; fine fire- 

 clay will be fused, and blown to slug in a few minutes, and 

 even the sides of the furnace are apt to give way. Though 

 thus admitting the fact of the increase of heat, when air loaded 

 with moisture is introduced into the furnace, yet he accounts 

 for the inferior produce of cast-iron in summer, compared with 

 that obtained in winter, by the state of the air, with regard to 

 moisture ; the quality of the air, according to him, becoming 

 contaminated for combustion, by Jwlding in solution a much 

 greater quantity of moisture. At the same time, he states a 

 fact, which I conceive corroborates what I have advanced with 

 regard to the action of water on fuel in furnaces. The pre- 

 sence of moisture in the atmosphere, he says, will tend in a 

 great measure to solve the curious phenomenon, of pig-iron 

 taking up less carbon in summer than in winter, although re- 

 duced with a superior quantity of fuel. The air discharged 

 most probably contains less oxygen, yet the metal is much less 

 carbonated than at other times, and he conceives that this 

 may be owing to part of the carbon being carried off by the 



