As regards the screw, the same points have to be considered, and a choice made amongst the various forms and proportions more or less successfully adopted at the present time. I have always found the reports made upon the results of various forms of screws and propellers, and the performance of different vessels, so little to be depended upon, even when apparently made in good faith, and the results obtained from good authority, that I have been long since compelled to adopt no conclusion, unless from results witnessed by myself or by persons observing for me. I have for some time past availed myself of every opportunity that offered of observing and obtaining something like accurate results upon the various points affecting immersion of paddles or screw, and I am engaged in considering those results. I have referred to the subject of protection from fire; it is one of considerable importance, and I have some hopes that a process, which has been recently patented by Lieutenant Jackson, may be successfully applied to rendering wood uninflammable. Some door panels have been already experimented upon with results which have induced me to pursue the experiments, and I am about to try the comparative inflammability of various qualities of wood, both prepared and unprepared; and if we can succeed in preventing the wood producing a flame, and thus communicating the fire; with the numerous metallic subdivisions we shall have in the ship, the spreading of fire, even from cargo or furniture, would become impossible. I am also engaged in determining the character and extent of mast and sail to be carried, as provision must now be made in the construction of the ship for receiving the masts. The Directors are aware that I have been in communication with Professor Airy as to the instruments which may be used in such a ship, to ensure more accurate and frequent observations, and as to the nature of these observations; an enquiry into which he has entered with that liberality and desire to assist all improvements, in navigation especially, for which he is so well known. Several new instruments are now making for trials. Sir W. Snow Harris has promised to turn his attention to the subject of the lightning conductors; and as soon as the iron work is a little more advanced, and while the form and position of all the principal masses are visible, the subject of local attraction and the adjustment of the compasses will be considered by those most competent to advise; and I am not without hope that the means of correction may be rendered much more certain and perfect than usual. I mention these, as some of the numerous points which require and are receiving attention.