He stated in his synopsis that calculations of the strength of thirty frames, in a ship that had answered exceedingly well, showed that a partial bulkhead or frame projected from the side of the vessel to the extent of only 20 inches was more than equal in strength to the thirty frames, if it were supported on two bearings at a given distance and weighted on the upper side in the middle. This frame, of 20 inches deep, would carry more than the whole of the thirty frames, and when the bulkhead was extended across to the other side of the ship there would be a great preponderance of strength in favour of the bulkhead. But, in dispensing with frames, it might, in some cases, be necessary to increase the plating for the sides, to give some additional strength. Since the strength of the materials increased as the square of the thickness, the addition of one-eighth to five-eighths of an inch plate increased the strength to resist a blow sideways, or in a lateral direction, by nearly 50 per cent. The strength of the vessel was further increased by placing the bulkhead in the widest part of the ship, amidships, and by other bulkheads placed midway between the midship bulkhead and the bow and stern, should it be deemed advisable; and also by the interposition of stiffening plates. Other strengthening means were also recommended. The vessel would be, he contended, “capable of sustaining a considerable pressure, either externally or internally, having round, swelling, or convex sides, with a ridge or rib on the lower side which answers the purpose of a keel.” Vessels of this type were expected to be much more economical to build, and no more expensive to run than those built on the ordinary lines. It was disputed whether a tubular vessel being without frames, floors, &c., would be strong enough for all purposes. An accident to Mr. Hodgson’s tubular cargo vessel, _The Carbon_, however, seemed to justify his contentions, for she stranded badly when being launched, so that her stern was submerged at high water. She was towed up the slip again, and refloated, and it was found that only two plates required repairs. _The Carbon_ was running until quite recent years in the east coast coal trade to London. Another important development in construction was due to Mr. J. Scott Russell, who has been described, like Sir I. K. Brunel, as a man before his time. Mr. Russell’s services to steam navigation in his exposition of the wave-line theory of ship construction were of incalculable benefit to the science. His object was to diminish the resistance offered by the water to the passage of the ship, and the modifications he made in the lines of the hull not only effected this to a very remarkable degree, but also increased the seaworthiness and speed of the vessels. He designed a number of small vessels suitable for special trades or to meet particular requirements.