in the Economising of Fuel. ISl 



when the steam was introduced with great rapidity, the in- 

 crease of heat was by no means so great as when thrown in 

 sloidij. Did the steam merely act as a blast, it ought to have 

 been the reverse. 



The experiments now detailed, arc, to my mind, sufficient to 

 pi'ove, that, by the transmission of steam, there is a considerable 

 increase of heat, without additional expenditure of fuel ; that, 

 in fact, the water, while passing, in the state of steam tbrcugh 

 fuel, not only acts as a sort of blast, but, at the same time, it 

 self undergoes combustion, by the formation and consequent 

 consumption of inflammable gaseous products. 



It may, however, here be objected to the use of steam, that 

 there must be a certain waste of fuel for the conversion of the 

 water into vapour. This must certainly be the case in many 

 instances ; but, in most places where furnaces are in use, there 

 is always the means of procuring steam, withovit any additional 

 expenditure of fuel. Even allowing that there is not, yet the 

 increase of lieat, by a comparatively small quantity of steam, 

 would, I think, more than compensate for any extra expendi- 

 ture for converting the fluid into vapour. But why, it may be 

 asked, not use the water in the fluid form ? The answer to 

 this is easily given. Not only must the fluid, the moment it 

 touches the fuel, deprive that part of the fluid of caloric, and 

 thus in a great measure diminish, if not entirely put a stop to, 

 the combustion there ; but also, by being imperfectly converted 

 into vapour, it must also be imperfectly acted on by the fuel, and 

 of course but partially undergo combustion. Hence, most likely 

 the cause of failure, in those cases in which a mixture of tar 

 and water has been allowed to fall, in a small sti'eam, on 

 fuel, as in the process lately recommended in some of the gas 

 establishments. In this case, the object in using the water is 

 altogether different from that which I propose. It is there 

 used with the view o{ j/ieldmg oxygen to the inflammable mat- 

 ter of the tar; but, as I have already stated, it is not likely 

 there should, in this way of using it, be any increase of heat ; 

 because, allowing that the oxygen of the water were to act on 

 the inflammable matter, tliat oxygen must itself, in uniting with 

 the carbon, and assuming the elastic form, acquire heat to re- 

 tain it in that state, whereas, in using steam, the latent heat has 

 been already acquired, and then, in undergoing decomposition, 



