44 PROCEEDINGS OF SECTION A. 



where 



o M + mi + mo m2,h 



{M+ mi + mzjli -mih {M + mj + W2)?i - mih 



^ M + mi + mz g nii h 



y = 



M + mi 1% M + mi I2 



1 M + mi + m^, 



mih {M + mi + m^li - mih 



15. If a periodic e.m.f. = P = p cos at act on the receiving circuit 

 of a wireless receiver, the equations for the currents in the circuits are 

 (see §§ 1, 2). 



riCi = - MDC. + P 

 r^Cz - - MDCi 



and for the P.D.s of the condensers in the circuits are 



riKiVi = - MK^DVz + D-^P 



uK^yz = - MKiDVi 



and as 



ri= Li 



^^ + A'i^- .,-.r.^^ + A'2^ 



D - " D 



the latter become 



(i)2 + ^^2) Y^^ _ ^^D2y^ ^ P] 



(Z)2 + ^22) Fo = - VZ^'^yX J 



where 



KiLi K^L-z 



as before. 



Thus, as the differential equations in § 14 connecting the pendulum 

 deflections are identical in form to the differential equations, given in 

 this paragraph, connecting Vi and F2 for the receiver coupled circuits 

 when receiving, and as the equations connecting the angular velocities 

 of the one system are also identical in form with those connecting the 

 currents in the other system, and as all the variables and initial 

 conditions for one system can be expressed by the same symbols as 

 the analogous variables and initial conditions for the other system, the 

 modification of the mechanical model proposed is an exact analogue to 

 the coupled circuits of a wireless receiver when receiving. 



