56 Proceedings of the Royal Society of Victoria. 



As the middle and end sections belong to the secondary coil, 

 ^2=.7, ^i=.5 and from the formulae in § 47, /., taking the upper 

 sign, we get 



.t'.,= -'— ^=-.000168, 



.909 

 x\= = .000404. 



From the formulae in § 49, 



for X^ and Xj, which are to be for a window in which ///^=:1.5, 

 we will take the mean of the values given in the table for win- 

 dows in which d' jb^=\ and b' jb^^l, and as /=:3, five sections, 

 W?i = 4-/3, we get 



.29 + . 41 

 X.,^-"^- =-.35 



.76 + 1.13 

 Xi= — ^ =: .945 



hence 



a;"2=-.000125, a;"i=. 000338. 



From the formulae in § 50, 



a;'%r=. 000002, .x-"', =.000014. 

 Hence, as 



Xp ^ a? ] -j- x' J -)- a; ^ , Xg ^^ a? 2 + -^2 + "^ s 



Xp=.0007U, a;s=— .000279, 



Xp +.a', r=. 000465. 



In Section I., § 23, it was shown that R, the drop per cent., 

 can be expressed in the form 



R=lOo|.TSin0+/Cos</,+x''(Sin^(/.+ -^)+/¥Cos'^.^ + 



Sin'-^di \ r / /-( 



— ^ ) + a;/Sin(f)Cos0 



■where x=^v(xn-\-Xs), /=i'{-+ |:=2 . 



Now to the first order ji^^:^ (full load values) 

 and 0=^/':[^ q.p. (see § 17) 



where z ( = 1 in this case) is the chosen ratio of copper to iron 

 losses at full load. 



