A.Marine engines are of two kinds,paddle engines and screw engines.

The screw-propeller vs. the paddle-wheel for marine propulsion.

A.The engines employed for the propulsion of screw vessels are divided into two great classes,geared engines and direct acting engines; and each of these classes again has many varieties.

The small leakage of water into the vessel which is thus occasioned, keeps the screw shaft in this situation always wet, and this is all the lubrication which this bearing requires or obtains.

There is a screw-driver belonging to Oaks lying in one of the empty lockersit has his name on the handle; and if we happened to drop it as we came away, I think that in the face of this row it would look uncommonly like his doing.

Because the shoe was pointed and had the remains of a rubber heelI could tell that by the big screw holes.

The Bayano was a new twin screw steel steamer of 5,948 tons.

These pieces are inclosed in a nickelized copper box provided with a screw cap, C. The resistance of both the receiver and transmitter bobbin is 200 ohms.

It arrives in large bundles, and is packed there, by means of a screw-press, in compact bales, for shipping, secured by rattan, each weighing two piculs.

a, Under part, with box, for the dry element; 6, roller for winding up the conducting-wires; c, dry element, with screw-clamp for attachment of the conducting-wires; c', conducting-wire leading to the screw-clamp, with contact-spring in c', Fig.

The steamship Ulunda, on the remarkable raising and recovery of which this paper is written, is an iron screw ship of 1,161 tons, until lately belonging to the Furness line.

We know that the neighbourhood of the Isle of Sheppey, at the mouth of the Thames, was covered with rich tropic vegetation; with screw pines and acacias, canes and gourds, tenanted by opossums, bats, and vultures: that huge snakes twined themselves along the ground, tortoises dived in the pools, and crocodiles basked on the muds, while the neighbouring seas swarmed with sharks as huge and terrible as those of a West Indian shore.

Two Royal Artillery 7 lb. screw-guns kept pace with the square, and a dozen white-bloused sailors, under their blue-coated, tight-waisted officers, trailed their Gardner in front, turning every now and then to spit up at the draggled banners which waved over the cragged ridge.

The screw on being put into revolution by the engine, preserves a spiral path in the water, in which it draws itself forward in the same way as a screw nail does when turned round in a piece of wood, whereas the paddle wheel more resembles the action of a cog wheel working in a rack.

By means of a screw-plug passing through the bottom and entering the face of the hub the heater may be applied and removed in the course of five minutes, an important fact, as will be seen hereafter.

The friction roller should be movable (on a screw thread), but so arranged that it can be fixed at any point, say by a lock nut, screw, clamp, or other simple means.

As regards propulsive efficiency, it would appear that the nearer the screws are to the middle line, the less is the resistance due to the shaft tubes and brackets, and the greater is the gain from the wake in the screw efficiency, but, on the other hand, the greater is the augment of the ship's resistance, due to the action of the screws.

Again, taking a screw tug boat on the river Thames, with blades of a totally different form to those used by Mr. Griffiths, we still find them set at the same angle, namely, 48 deg.

"'Complete set superfine human osteology strongly articulated with best brass wire and screw-bolts, with springs to mandible and stout iron supporting rod.

I knocked at the door, and was answered by a red-haired young woman, with a silly grin on her face, the smirk flanked on each side with cork-screw curls which hung down over her bright blue dress; which, as I could see, was pulled out at the seams under her round and shapely arms.

When the pitch of a screw increases in the direction of its diameter, the central part of the screw will advance with only the same velocity as the water, so that it cannot communicate any centrifugal velocity to the water; and the whole slip, as well as the whole propelling pressure, will occur at the outer part of the screw blades.

At length, in 1841, Captain Stockton was authorized to proceed with the construction of a screw steam frigate of about one thousand tons.

16 Paddle " During the early part of 1917 it was decided to substitute 56 screw minesweepers and 8 paddle sweepers for the approved programme of this class of vessel and to add another 50 screw minesweepers to meet the growing mine menace, as well as to substitute 115 drifters for 50 of the trawlers, and to request the Canadian Government to build 36 trawlers and 100 drifters mainly for use in Canadian waters.

" The slate on the floor being examined, there was found on the outside (it was a screw-slate)

The standard screw machines used for metal tests are also used for wood, but in the case of wood tests the readings must be taken "on the fly," and the machine operated at a uniform speed without interruption from beginning to end of the test.