2 (z1 − z3) = OM2 − 2OM·ON cos θ + ON2= MN2.
OM·ON OM·ON

(51)

With z2 = z3, κ = 0, K = ½π; and the number of beats per second of the axis is

m= n z1 − z3= MN n,
π π2 √ (OM·ON)

(52)

beating time with a pendulum of length

L = l= 4OM·ONl.
½ (z1 − z3) MN2

(53)

The wheel making R/2π revolutions per second,

beats/second= MN n= C· MN,
revolutions/second √ (OM·ON)R AOC′