# How to use *Bq* in a sentence

If

**BQ**be the direction for the first minimum (the darkness between the central and first lateral band), the relative retardation of the extreme rays is (mn+1)X.Suppose now that X+SX is the wave-length for which

**BQ**gives the principal maximum, then (mn+1)A=mn(X+SX); whence OX/X= limn.The equation of the latter, referred to its principal axes, being as in II (41), the co-ordinates of the point J where it is met by the instantaneous axis are proportional to p, q, r, and the direction-cosines of the normal at J are therefore proportional to Ap,

**Bq**, Cr, or X, u, v.If we now apply them to the case of a rigid body moving about a fixed point 0, and make Ox, Oy, Oz coincide with the principal axes of inertia at 0, we have X, u, v=Ap,

**Bq**, Cr, whence A (B C) qr = L,To show the cause of this motion, let

**BQ**represent a section of an oblate spheroid through its shortest axis, PP. We may consider this spheroid to be that of the earth, the ellipticity being greatly exaggerated.Advertisement