ON SUPPIEHEATED STEAM. 



101 



a slow and uniform degree. This table represents 

 the pressures at corresponding temperatures : 



Table II. 

 Sub-iaturated or Superheated Steam. 



this (the boiler) is the lion, this (steam- chamber), 

 on the other hand, is the lamb ; this sub-saturated 

 steam will increase only in a uniform pressure 

 with its temperature (the reason of which will be 

 explained further on). The Table No. II. gives the 

 figures of its increase of heat and temperature, 

 which you will perceive is uniform ; and so little is 

 the increased expansion of sub- saturated steam, 

 that by increasing the temperature 230°, you only 

 get an additional expansion of half its volume, or 

 *7\ lbs. additional pressure to the square inch ! 

 What do we find in the case of the saturated 



