144 Dr. S. TV. Richardson on the Magnetic 



Analysis of upper half {by Mr. Dawe). 



Aluminium 9*89 



Combined Carbon 2*80 



Graphite traces 



Silicon 2' 75 



Sulphur traces 



Phosphorus 0*57 



Manganese trace 



Copper nil 



Chromium nil 



Arsenic nil 



Iron (by difference) 83'99 



n , . .^. 100-00 



Dimensions of King. 















* 



i 



2.-CJ2. 



? 



r i 





<ss fc-57 S> 



< 





External diameter 

 Internal „ 



Mean ,, 



6*57 cms. 

 3-90 „ 



5-23 ;; 



Mean thickness 2*92 „ 



Mean section 3'88 sq. cms. 



Other data. 



Turns in Primary .... 63 

 Turns in Secondary .... 36 

 Standard Mutual Inductance used = 1*155 x 10*. 

 The curves connecting- B and T (H= const.) for this alloy 

 are shown on figs. 15 and 16. 



A studv of these curves in conjunction with the correspond- 

 ing ones for the Alloy Xo I leads to the conclusion that the 

 maximum value of the induction is probably reached at a 

 temperature of about — 90° C. The great change in the 

 induction between this temperature and 4- 100° C. is very 

 striking, the value at 100° being about one-quarter of that at 

 -90° C, and about one-half of that at 20° C. 



The curves show for weak fields a second maximum between 

 300° and 400°. after which the induction falls off to a 

 minimum value at about 460° when the permeability = 1-7. 

 All the methods for varying the temperature {vide § IV.) 

 were called into requisition in the experiments on this alloy. 

 The method used in obtaining each series of observations 

 is indicated above the series in the tables given below. 



