STEAM NAVIGATION. It would seem that navigation, being founded on the bases of geometry and astronomy, would be but one system, practicable alike by the commander of a sailing ship or of a steamer ; that practice attained in navigating one class of vessels would be equally available for the safety of the other ; but it is not so. As well may we compare the driving of a spirited horse in a light gig to the driving of a waggon team : there are points of skill iu each, and proficiency is also attainable in each, but interchange the drivers, and It is probable that neither of the vehicles would be so well conducted as before :—and thus it is with steam navigation. The sailor of the old school (for there is specifically a new one), is accustomed to have Ills eyes aloft ; and the trim of his sails, and the steadying of a bowline here, and the puling upon a brace there ; the habitual look to wind ward for coming weather, ite. ; these form the main sources of that unceasing vigilance without which no one can be fit to command.
The navigation of a ship (In its abstract meaning), is with the sailing commander a mere routine. A course of measured attentions to certain established customs, handed down from generation to genera tion, and performed at definite periods, leaves his mind, after those periods have passed, nearly free from the duties of calculation alto gether. But in the new school, things are far different, and it will be useful in this place to illustrate the present state of the subject, by examining into what really constitutes this differatice, for it becomes a question of training and qualification.
We have only to refer to our article COLLISIONS AT SEA, to show that fearful innovations have followed the introduction of steam into our sea services—affecting in a high degree the safety of life; and wo also refer to Sures and SMITING to show what laws are found necessary in preventing such insecurity, Fearful then must be the increased responsibilities of a commander of a steam vessel. Nor does this admit of limitation, for the very causes of all this aro in themselves progressive.
Very much may be attributed to the increase of speed in steamers ; yet there are other influences which affect steam navigation with peculiar force : among these' may be noticed the wide prevailing interest that owners, of steamers in particular, feel in the rapidity of • their voyages. Hence, every advantage which can be taken to accom plish this, is considered part of a commander's duty—and his position, therefore, depends much upon his habitually making a quick passage.
The following will explain the work of each kind of navigator. In the sailing ship, the master daily at 1 bell in the forenoon watch (half Fast S a.m.) takes his sextant upon deck to obtain an altitude of the sun, in readiness for working his time at ship : he defers this work till noon, at which he will have obtained his ship's latitude from a meridian alti tude. During the forenoon, or from nine o'clock, his only work con nected with navigation-proper, is an occasional glance over the side of the ship, in order to estimate the ship's "way " (velocity), and also at times at the binnacle compass to get an opinion as to the accuracy of the course about to be marked on the leg-board. [Dean-ItEesoNrao.] The ship's position at noon having been pricked off upon a chart, and the log duly written up as soon after noon as convenient, the remainder of the day calls for no further computations,—unless, as it occasionally happena, sights for the time were not procurable in the forenoon, and are taken at about 3 pan, it being better to obtain them when the sun is about three hours from the meridian. Occasionally, a sailing navi gator may see fit to try a lunar for his longitude, but this is entirely optional ; or, perchance, in the evening an intelligent merchant captain may desire to verify his position by observation of a star, &c. So then as regards routine observation, the work of a sailing commander is very light. For even, if in addition to his daily routine he be approach ing land, it entails no serious loss or labour to " lie-to " for a few hours till daylight.