ON" SUPERHEATED STEAM. 



195 



standing of the subject, to explain two or 

 three. One mode is shown by the diagram Fig. 20, 

 in which the steam is superheated in a mass of 

 pipes, placed in the flue between the boiler and 

 the shaft. Another is the conducting the steam 

 from the boiler through pipes arched over the fire. 

 A third is by conducting it through a set of pipes 

 fixed in a separate furnace ; and it is by the latter 

 mode which I have chiefly gained my experience. 

 A fourth mode is according to a patent of my 

 brother, Mr. S. Childs, viz., by double or cased 

 vessels with a fire underneath, which is a very 

 excellent plan for heating or distilling fluids. The 

 steam may be also heated in a separate chamber, 

 as in the case of the vulcanizer, or with a coil of 

 gas pipe underneath the top chamber (Fig. 25). 



Fig. 25. 



