1912-13.] Error caused by “ Lag” in a Recording Instrument. 113 
Fig. 5. 
As already found, let the equations to the two curves be 
w = ye~ M 
then 
and 
ye 
V= — [1 - e -(*+°-V)t]; 
k + crV L 
v fl = w k and v h = w h 
-kt 4= rV 2 [i _ e -Vc+o-V)h j 
k-aY 
- kt 3 = _y_ V2 , [ l _ e - (*+*v)< 2 1 
' k + <rV L 
Let R = number of revolutions actually described 
.-. R = 
Ch rt 
L vdt+ L 
wdt 
°’ V ' 2 (* 2 - q) + — (e-(*+«-v)<a _ e-(^+o-v)«i) _ I( e -^4 - e-*%) 
k + <tV 
o-V 2 
k crV 
VOL. XXXIII. 
(L - L) 
(& + o-V) s 
O ' 2 v 3 
(k+o-yyk 
( e -(fc+aV )< 2 — g-Cfc+o-V)^) # 
8 
