through, given above, do not measure the inclination of the ship to the surface of the water, but only her inclination to the true vertical. Pitching and lifting are produced by the vessel endeavouring to follow the slope of the waves, or, roughly speaking, to keep her displacement the same as in still water, both as to volume and to longitudinal distribution. “As to the depressing effect of the water on the bow, a layer of water one foot deep over the entire forecastle exerts a pressure of 65 tons; this will produce a change of trim of 11 inches, together with an increase in the mean draught of 1¾ inches; i.e. the draught of water forward will be increased by 7¼ inches, while that aft will be diminished by 3¾ inches. A layer 2 feet deep will have double this effect; one 3 feet thick will have treble this effect; and so on up to a considerable angle. This follows from the fact that the front slope of the longitudinal curve of stability, up to a considerable angle, is very nearly straight. Hence the effect, even of a large body of water passing over the forecastle, tending to make the vessel dive down head foremost, is small, and of no importance. It modifies, however, the transverse stability. When proceeding head to sea there was no appreciable rolling motion. With the wind and sea on the bow she pitched considerably less than when going head to sea, but rolled through 5 degrees or 6 degrees. With the wind and sea abeam, lying passively in the trough of the waves, the maximum angle rolled through was 14 degrees from port to starboard, 6½ degrees to windward, and 7½ degrees to leeward, and this without perceptible pitching. When, however, proceeding at about seven and a half knots, with the wind and sea on her quarter, she rolled through 27½ degrees from port to starboard, 13 degrees off the perpendicular to windward, and 14½ degrees off the perpendicular to leeward, besides also pitching through some 4 or 5 degrees. This is by far the greatest angle she has ever rolled through. It is the apparent period of the waves, i.e. their period relatively to the ship, which operates in making a vessel roll. The motions of the vessel, both as to pitching and lifting and to rolling, were extremely easy. She, indeed, claims to have behaved better than her companion, the _Agincourt_. Certainly, her rolling motion was somewhat slower, and she rolled less deeply; when the _Agincourt_ was rolling 17 degrees from port to starboard, the _Devastation_ was only rolling 14 degrees. As to pitching, the _Devastation_ may fairly claim to have had the advantage, for, as we have seen, although the _Agincourt_ pitched rather less, her bow moved vertically through a greater distance, so much so that while going head to sea at seven knots she shipped a sea over her high forecastle, showing that she could not be driven under the circumstances at a much higher speed with at least anything like comfort.”[43]