EXPERIMENTAL STUDY OF HEAT LEAKAGE. 



741 



h. The V-type of radial flow plug case. 



The apparatus illustrated in Fig. 3 will be referred to as the V-type 

 of plug case, for the sake of brevity. The design, which is due to 

 H. N. Davis, under whose direction the apparatus w as also constructed, 

 was adopted with the two-fold purpose of retaining the convenience 

 of approximately vertical thermometers and of doing away with the 



Figure '3. Radial flow plug and case, V-type. 



lengthy cross channel of Fig. 1. It was also possible to employ the 

 oil tank, stirrers, cradle, secondary superheater, etc., which had been 

 used with the apparatus of Fig. 1. 



The plug P, in Fig. 8, is of alundum, and was obtained from the 

 Norton Alundum Co., of Worcester, Massachusetts. It was secured, 

 as shown, to a brass collar by the device of plating from a solution of 

 copper sulphate onto the inside of the collar, through the alundum, 

 from a copper electrode placed just inside the open end of the cup. 

 The copper fills up the pores of the alundum and a mechanically rigid 



