The following Elementary Lessons in Steam Machinery were prepared for the Naval Cadets in H.M.S. Britannia, and represent a systematic course of simple instruction preparatory to a more thorough study of the whole subject.<br><br>The syllabus of subjects dealt with is based on the plan adopted by the Science and Art Department.<br><br>The aim of the earlier lessons is to lay a sound basis of instruction in the elements of construction and mechanism, also in those mechanical details which students are usually expected to learn by workshop experience, and are not found in Steam Engine Text-books.<br><br>Nothing is stated except the conclusions arrived at by experience, and the simplest examples are given to illustrate the various details of Marine Engines. Untried experiments are not referred to, but the information given is up to date, and obsolete ideas have been as far as possible avoided.<br><br>The notes on construction of a Battleship will serve as an introduction to the large subject of modern ship construction, treated of more fully in the Text-book of Naval Architecture, which has been prepared by order of the Admiralty.<br><br>The editor wishes to express his indebtedness to J. T. Corner, Esq., Inspector of Machinery, R.N., Chief Engineer of Portsmouth Dockyard, and to F. J. Sercombe, Esq., Engineer, R.N., for much valuable assistance in preparing this edition. He is aware that the present is a most unfavourable time for reprinting a book dealing with Naval Boilers; but he has done his best to represent the conditions as they now exist.