While we have thus lightly run over such duties of the master of a merchant ship as are imperatively demanded of him by his position, it must not be lost sight of that there are many things that he should be and know that, while not compulsory, are most necessary, and no master who is really attached to his profession will neglect them. For instance, the Board of Trade has a voluntary examination in "steam," which is based upon some of the most elementary facts connected with running marine engines. A master may pass in steam or he may not, as he pleases, and it is doubtful whether many owners are influenced in their choice of a master to command one of their ships by the fact that his certificate is endorsed "passed in steam." Yet it should be obvious to all that for a master of a steamship, however small, to be ignorant of at least the broad principles of marine engineering must be a terrible defect. He should certainly be able, in the event of his engineers dying or becoming incapacitated, of taking charge of the obedient monsters below, and running his ship, if not to her destination, to some port where the need could be supplied; and, in any case, he should know well under what conditions those engines do their work, that he may be the better able to appreciate his engineers' reports, and for other reasons which need not be stated. Any lack of this knowledge on the part of a steamship master is the more to be deprecated because he has such splendid opportunities and such ample time for learning.