y antes Watt, yunr. 235 



answered one extremely good end : ii has made your 

 engines general topics of conversation, and consequently 

 universally known, which they were by no means before in 

 this country.' On June 14, 1785, Watt took out a patent 

 * for certain newly improved methods of constructing fur- 

 naces or fire-places for heating, boiling, or evaporating of 

 water and other liquids which are applicable to steam- 

 engines and other purposes, and also for heating, melting, 

 and smelting of metals and their ores, whereby greater 

 effects are produced from the fuel, and the smoke is in 

 a great measure prevented or consumed/ which newly 

 improved methods he describes to consist ' in causing the 

 smoke or flame of the fresh fuel, in its way to the flues or 

 chimney, to pass, together with a current of fresh air, 

 through^ over, or among fuel which has already ceased to 

 smoke, or which is converted into coke, charcoal, or cinders, 

 and which is intensely hot, by which means the smoke 

 and grosser parts of the flame, by coming into close 

 contact with, or by being brought near unto the said 

 intensely hot fuel, and by being mixed with the current of 

 fresh or unburnt air, are consumed or converted into heat, 

 or into pure flame free from smoke.' * I put this in prac- 

 tice,' he continues, ' first, by stopping up every avenue or 

 passage to the chimney or flues, except such as are left 

 in the interstices of the fuel, by placing the fresh fuel 

 above, or nearer to the external air, than that which is 

 already converted into coke or charcoal ; and by con- 

 structing the fire-places in such manner that the flame, 

 and the air which animates the fire, must pass downwards, 

 or laterally, or horizontally, through the burning fuel, and 

 pass from the lower part, or internal end or side of the 

 fire-place, to the flues or chimney. In some cases, after 



