TUBULAR SUPERHEATING BOILER. 377 



into a greater bulk of steam, of about the same expansive force 

 that it had acquired iu the boiler, by which means I obtain a 

 greater volume of steam for use in the working cylinder than 

 the boiler alone would supply; and in order still further to 

 augment this volume of steam, I place the working cylinder 

 within a case constituting a part of the flue or chimney, that 

 the cylinder may be kept considerably hotter than the steam 

 employed in it by absorbing a great portion of the heat re- 

 maining in the flue after having heated the boiler and the dry 

 pipes, which heat would otherwise pass away out of the top of 

 the chimney and be wasted, but by this arrangement is con- 

 verted into a useful power by further expanding the steam in 

 the cylinder. 



" And I do further declare, that in carrying this part of my 

 said improvement into effect, I do not find it necessary to con- 

 fine myself to any particular form of boiler, or arrangement of 

 pipes, in which the steam is to be heated ; but by preference, 

 as being very compact in form, and economical of fuel in using, 

 I make my boiler of a number of upright pipes, standing upon 

 and communicating with a tubular ring placed around and a 

 little below the fire-grate ; these pipes all surround the fire- 

 place, except two or three, the lower ends of which are elevated 

 above the fire-door, but connected at the bottom by a branch 

 pipe united to one of the adjoining upright pipes, thereby 

 leaving an opening or place of access to the fire. These pipes 

 all extend upwards to the height of several feet, according to 

 the quantity of steam required to be raised, combined with 

 local convenience, for it is obvious that the power of this boiler 

 to raise steam may be increased either by increase of the length 

 of the pipes, of their diameters, or of their numbers. And I do 

 lay upon the upper ends of the pipes hereinbefore described 

 and connect with them a tubular ring similar to that upon 

 which the pipes stand, the two rings and the upright pipes 

 forming together a vessel in which water has free communi- 

 cation by means of the bottom ring to stand at the same level 

 in all the pipes, and the steam has free communication to pass 

 from all the pipes into the upper ring ; and I do, for the sake 

 of obtaining great heat, place my system of dry pipes over the 



