On shore, education and business are two separate things, one of which does not begin till the other ends; while, on board ship, the two always go hand in hand. As the lessons of the teacher may be put in practice immediately, the utility of theoretical knowledge is exhibited on the spot; and thus a gradually increasing impulse is given to the whole course of study. A boy who learns from his master what the word Latitude means, and what is the method of obtaining it, instantly runs upon deck, takes a quadrant in his hand, observes the sun’s meridional altitude, and is filled with amaze and delight on discovering: within what small limits he has been able to determine the ship’s place relatively to the equator. Next day he sets to work with increased eagerness to conquer the more difficult problem of finding the Longitude, which he has immediate opportunities of bringing to the test of actual experiment. The theory of Gunnery, likewise, when studied by itself, is frequently found to be intricate, and often far from satisfactory; but, when all its results can be brought to the test of experiment, the aspect which this very important pursuit assumes is totally different. How few officers, for instance, understand correctly the meaning of the elementary term Point Blank, or have any useful conception of the mathematical principles which it involves! How often do we hear people gravely assuming that the shot rises between the gun and the point-blank mark! The laws which regulate the action of fluids directed against plane surfaces are by no means easily explained when grappled with alone; but, when brought to bear on the use of the rudder, or the trim of the sails, there is hardly a boy afloat who fails to appreciate the value of true science over what is called ‘rule of thumb;’ or rather, who may not soon be taught to feel the mighty advantage of uniting the two, so as to make theory and practice mutually assist each other.