AND SURFACE CONDENSER. 



339 



George Rennie. His old friend Mr. Mills took an 

 interest in it, and wrote, " I am going to meet Captain 

 Symonds at Woolwich again to-morrow, and hope 

 to be able to persuade him to use his influence with 

 Sir T. Hardy/' 



"LAUDERDALE HOUSE, HIGHGATE, 

 " ME. GILBERT, August iQth, 1830. 



" Sir, The boiler with the fire-place, cold air tubes out- 

 side the boiler but within the steam-case, fire-tubes iu the boiler 



FIG. 1. PLAN SECTION. 



from the top of the fire-place to 

 the top of the boiler, the ash- 

 pit close, except a small door to 

 clear out the ashes. 



" The design is for the cold 

 air to pass down from the top 

 of the boiler through the air- 

 tubes within the steam-case sur- 

 rounding the boilers, becoming 

 heated in its passage by con- 

 densing the steam in the case, 

 and then to pass up through 



FIG. 2. ELEVATION SECTION. 



the fire-bars in, the hot state, nearly as hot as the steam in 

 the case; because this air, heated to nearly 212 degrees by 



1 a, steam-case; I, boiler-case; c, 

 space for condensation of steam ; r/, 

 water and si cam space ; c, fire-tubes ; 

 /, fire-box; g, fire-door; //, tirr-bars ; 



i, ash-box ; ./, ash-box door ; &, air- 

 tubes in condenser ; I, chimney ; m t 

 water level ; a smoke-jack fan draught. 



