USEFUL FORMUL. 







i= 7}/T? . (34) 
gi_g _(2nV 
f ae ea, (38) 
fh 
0 (38 a) 
V1+ (xT/2 +)? 
Ty = T {1 —4(«T/27)*} when « is small (39) 
a Sa SEV {1 eee 
(2) “(e)/ +e) J oo 
KT,\' ___log,’« iz log’ e 
(5 ") m+log’e« 1.862 + log’ Soe 
KT. _ A __ 0.7433 
—_ = — = ] be! 
2r n ae i 
: = +: from (44) 
n A, —A +1 
8 = 2s 54 
A, 417+ Aoay1 ( ) 
A,? — A, A, 
Dp 8 1442 y) 
Sacer’ ake (52) 
—1 A? ||, — A, A, 
ip as n+1 1442n+1 57 
e+1 (A, — Ays1) — (Angi — Aons1) ( ) 
4.605 A,— A 
Some te ] o 1 n+1 
: nT ils A, 41 — Asay (66) 
W= I (79 a) 
log’ Py ig hoe 2 
4 —____o sf —_ — yd 
\ eee * Sa. | 
We 
TaN LY PY : kT PN CPO 4r\i/ P\* 
rM Gok tf Wy Bet a | OU Bete! HY fen Fay fee ek hae 
VE) He) 1} EG) +) @) 
at (Q/Tr)? (91) 
* agi (BY 4 Che 
1.862 + log? e\ Ty T 
V=nl/L=inl/L' =a,;/L'id (29) and (33) 
where a, is the displacement of the pointer corresponding to an angular displacement @ of the 
pendulum, 
192 
