I need hardly remind you that, owing to the lateness of the season, you will require that the vessel should be prepared to run her first voyage almost immediately after the engines are fixed. You will remember, also, that it will be the longest voyage yet run; that in the event of unfavourable weather a total failure might be the result of the engine not working to its full power, or consuming too great a quantity of coals--a very common occurrence with engines apparently well made, after six or eight days’ constant work; and, lastly, that the future success of the boat as a passenger ship--nay, even of the company’s boats generally, and, to a great extent, and for some time, the reputation of Bristol as an American steamboat station, may depend upon the success of this first voyage. It is indispensable, therefore, to secure as far as possible a machine which shall be perfect in all its details from the moment of its completion. There may be time for a few trials for ascertaining the fact of its completion, but there will be none for effecting any alterations should they be found necessary, or for making any experiments. The machinery which you require to be so perfect is by no means an ordinary steam-engine. Marine engines of 80 or 90, and even some of 100 horse-power, are mere models on a large scale of the ordinary-sized engines. Engines of 160 or 180 horse-power each would be unmanageable without many material modifications in the details; the arrangement must be different, and, as the strength of materials remains the same, the proportionate dimensions of the parts must be modified. Many contrivances of this description have been introduced into the large engines of 110 horse-power each made for the Navy. From 110 to 160 is still another and a very great stride. Those who have led the way in the first step are certainly the most likely to be aware of the difficulties of the second, and to be able to appreciate them better, and be more prepared to overcome them than those who have as yet only manufactured, however successfully, engines of the ordinary class. Of three parties tendering.... Messrs. Maudslay have made by far the largest number, and have for some years led the way in the introduction of the largest armed steamboats; and there can be no question as to the fact that they are the oldest manufacturers of marine engines, that they are themselves the originators of the greatest number of the improvements of the day, that they have made the largest engines yet made, and the greatest number of large engines of all sizes; and, lastly, that they have the principal supply of engines for the large war ships now used for the Navy, and have had hitherto the sole supply of all above 70 horse-power.