EXPERIiMENTS ON THE CONDENSATION OF STEAM, 



419 



possible, by ta suitable modification of the surface-condenser method, to 

 obtain values of the condensation considerably in excess of those given by 

 the formula deduced from the temperature cycle observations. 



To accomplish this, it is necessary to eliminate as completely as possible 

 the resistance to the passage of heat of the water-films between the steam 

 and the metal, and between the metal and the circulating water, and at 



STEAtl INLET 



'WArCK OUTLET 



(^3~^ 



^—ro SreAM THCK«OmCT£R 



'WATER It. LET 



\ TO SEPA/IATOR 



the same time to measure as accurately as possible the temperature of the 

 metal. 



These considerations led to the form of apparatus shown in the figure. 

 The resistance to the passage of heat from the metal to the condensing 

 water in this apparatus is practically eliminated by employing a thick 

 cylinder, 5 in. diameter and 2 ft. long, with a screw thread cut on its outer 

 surface. Water from the high-pressure mains is forced to circulate round 

 this surface with a very high velocity, in the narrow space between the 



E B 2 



