**BM**- Within quite recent years, however, a special school q Y P has arisen with the main object of treating the processes of evolution quantitatively.

C, Cellular tissue of the integument; **Bm**, basement membrane; cire.

Denoting the distance AM by d 1, **BM** by d2, and AB by 1, we have for the force at M due to the magnetism of the rod H P =d 12 - horizontal component (dla - d 2 3).

Hen d =a the general formula becomes sin' Zm7r **Bm**: B = (3), showing that, when m is even, B m vanishes, and that, when m is odd, B m: B =1/m272.

Tons, (4) w denoting the density of water in tons/ft.', and W =wV, for a displacement of V ft.3 This couple, combined with the original buoyancy W through B, is equivalent to the new buoyancy through B, so that W.BB 1 =wAk 2 tan 8, (5) **BM** =BB 1 cot B=Ak e /V, (6) giving the radius of curvature **BM** of the curve of buoyancy B, in terms of the displacement V, and Ak e the moment of inertia of the water-line area about an axis through F, perpendicular to the plane of displacement.

The naval architect distinguishes between the stability of form, represented by the righting couple W.**BM**, and the stability of ballasting, represented by W.BG.