While the engineer’s mind was still occupied with the subject, an accident occurred to the _Prince of Wales_ iron steamship, at Blackwall, which singularly corroborated his views as to the strength of wrought-iron beams of large dimensions. When this vessel was being launched, the cleet on the bow gave way, in consequence of the bolts breaking, and let the vessel down so that the bilge came in contact with the wharf, and she remained suspended between the water and the wharf for a length of about 110 feet, but without any injury to the plates of the ship; satisfactorily proving the great strength of this form of construction. Thus, Mr. Stephenson became gradually confirmed in his opinion that the most feasible method of bridging the strait at Menai and the river at Conway was by means of a hollow beam of wrought-iron. As the time was approaching for giving evidence before Parliament on the subject, it was necessary for him to settle some definite plan for submission to the committee. “My late revered father,” says he, “having always taken a deep interest in the various proposals which had been considered for carrying a railway across the Menai Straits, requested me to explain fully to him the views which led me to suggest the use of a tube, and also the nature of the calculations I had made in reference to it. It was during this personal conference that Mr. William Fairbairn accidentally called upon me, to whom I also explained the principles of the structure I had proposed. He at once acquiesced in their truth, and expressed confidence in the feasibility of my project, giving me at the same time some facts relative to the remarkable strength of iron steamships, and invited me to his works at Millwall, to examine the construction of an iron steamship which was then in progress.” The date of this consultation was early in April, 1845, and Mr. Fairbairn states that, on that occasion, “Mr. Stephenson asked whether such a design was practicable, and whether I could accomplish it: and it was ultimately arranged that the subject should be investigated experimentally, to determine not only the value of Mr. Stephenson’s original conception (of a circular or egg-shaped wrought-iron tube, supported by chains), but that of any other tubular form of bridge which might present itself in the prosecution of my researches. The matter was placed unreservedly in my hands; the entire conduct of the investigation was entrusted to me; and, as an experimenter, I was to be left free to exercise my own discretion in the investigation of whatever forms or conditions of the structure might appear to me best calculated to secure a safe passage across the Straits.” {329a} Mr. Fairbairn then proceeded to construct a number of experimental models for the purpose of testing the strength of tubes of different forms. The short period which elapsed, however, before the bill was in committee, did not admit of much progress being