A few years ago Lieut. Molyneux Shuldham, R.N. took out a patent for revolving masts, the enrolled specification of which exhibits in sixty-five diagrams and designs, numerous modifications and applications of the principle to various descriptions of inland as well as sea-going vessels. As our space will only admit of a brief outline of the nature of the invention, we must refer the reader who may be solicitous for the details, to the inrolled document in Chancery-lane, and to some beautiful models illustrative of the inventions (constructed by the talented inventor's own hands), exhibited at the National Museum of the Mechanical Arts, in Leicester-square, London. The mast instead of being, as in ordinary vessels, a fixture, is herein made to revolve upon its axis, or turn horizontally upon its heel, carrying with it the sails, yards, and other rigging attached to it, and thereby instantly changes the direction of the vessel's motion. The power required to perform these evolutions may be the wind or manual labour, or both conjointly. As the action of the wind will naturally tend to produce the desired effect in both cases, whatever manual force may be required to assist the operation must be very little indeed; that is to say, according to modern phraseology, the maximum of effect is produced by a minimum of labour. It will be evident from this arrangement of the inachi
nery of a ship, that fewer hands will be required to work it, that the running rigging may be much simplified and curtailed, and the wear and tear greatly reduced. These improvements are considered applicable to open boats, deck boats, and small craft in general ; to vessels employed in inland navigation, coasting vessels, and particularly those navigating intricate channels and rivers. But Mr. Shuldham does not consider them applicable to vessels of war and vessels of small tonnage, that carry lumber in their decks, owing to the room required for the revolving bases of the masts. The masts are variously supported, according to the tonnage of the vessels : in decked boats and small vessels, an iron or wooden pivot is sufficient; in larger vessels anti-friction rollers are fixed to the revolving base, which work between two annular plates, secured to the gunwhales and deck.