renders possible between the behaviour of the iron-clads and the wooden two-decker, the latter proving the heaviest roller in the squadron. In Admiral Yelverton's Report [on the Channel Squadron] for 1866, there are given examples of the comparative rolling of several of the iron-clads, obtained from three days' observations, of which the mean results are:- Achilles and Bellerophon, 6.6 degrees; Hector, 11.3; Ocean, 14.3; Lord Clyde, 16.1; Pallas, 17.3. ... The small size of the Pallas, as compared with the other ships, puts her at a great disadvantage as regards comparative rolling in ordinary waves." "The Achilles has a distance of about 3 feet between the centre of gravity and the metacentre, and is a remarkable steady ship; whereas the Prince Consort, with a distance of 6 feet, rolls much more than the Achilles." Carrying capacity of wood hulls compared with iron hulls Parkes claims, "In the Service their construction was regarded as a retrograde movement, their very heavy wooden hulls having only 80 per cent of the carrying capacity of iron ones." However, this view is mistaken and unfair. The following table is taken from Reed. It shows that in 1861, wooden-hulled ironclads had a greater carrying capacity than contemporary iron-hulled designs. It is of course true, that when Reed's bracket-frame system was introduced with the Bellerophon (laid down December 1863), iron hulls became much lighter for the same strength. Machinery "The Prince Consorts were all three engined by Maudslay and Sons on an identical plan, … the arrangement of their machinery was very unusual, though not entirely without precedent in wooden-hulled steamers. When horizontal reciprocating marine engines were being installed it was necessary as a first step to select a position for the cylinders with enough athwartship level to give a proper length for the stroke… As the Prince Consorts had been shaped with an underwater run of the old style before being ordered for conversion… their floors rose considerably abaft the midship point; which meant the only practicable position for the much larger engines they were to carry was in the added central body halfway between bow and stern." (Iron-hulled ironclads had their engines further aft.) "Return-connecting-rod engines were installed." Royal Oaks boilers were in one group of six on the forward side of the engines. The Prince Consorts larger engines required more boilers, so they had two groups of four; one set forward of the engines,