Analysis Of The Various Plans For Propelling

The ordinary or undershot Water-wheel - defects of. - Galloway's Cycloidal Paddle-wheel. - Gemmel's Paddle-wheels. - Galloway's double oblique Wheels. - Buchanan's Parallel Float-wheels. - Oldham's vibrating Float-wheels. - Morgan's vibrating Float-wheel. - Dawson's radiating feathering Paddles. - Stead's Ditto. - Leeming's eccentric sliding Floats. - Endless chain-propellers. - Spurgin's endless Chain-propeller. -Stevens's crank-action Propellers. - Nairne's collapsing Propellers. - Perkins's oblique sculling Wheel. - Linnaker's Propelling Pumps. - Busk's Hydraulic Propellers. - Ericsson's screw Propeller. - Hunt's propelling and steering Screw. - Canal Navigation. - Seaward's Spike wheel. - Saxton's differential warping Wheels.

In the present section we shall consider the means by which the power of steam is applied to the propelling of vessels. Numerous plans have been brought forward for this purpose, but they are all reducible to a few classes; the difference between those in each class being merely modifications of some particular principle. We shall therefore limit ourselves to a description of one or twoexamples from each class. In most of the various plans adopted or proposed for propelling vessels by steam, the motion is produced by one or other of the following means.

1. Wheels on the principle of the undershot water wheel, with fixed floats variously arranged. - Illustrated by the examples herein given of Galloway's and Gemmel's wheels.

2. Wheels with moveable floats turning on horizontal axles or spindles.- Illustrated by the inventions of Buchanan, Oldham, and Morgan.

3. Wheels with moveable floats turning on radiating axles or spindles.- Examples of which are produced in the inventions of Dawson, Oldham, and Stead.

4. Wheels with floats sliding along the arms, towards, and from the centre of the wheel. - Sufficiently illustrated by the invention of Leeming.

5. Ranges of paddles attached to endless chains. - Shown in the invention of Spurgin.

6. Ranges Of Paddles Attached To Cranks

Illustrated by Stevens's invention.

7. Paddles which collapse during the return stroke, so as to offer less resistance at that time, commonly known as the duck's-foot apparatus. - An example of which is given in 'Nairne's invention.

8. Sculling

Exhibited in Perkins's invention.

9. A stream of water expelled from the vessel, either by pumps or by the direct action of the stream, on the principle of Savery's engine. - An example of which is afforded in the invention of Linnaker.

10. By the reaction of the water, on the principle of Barker's mill. - Exhibited in the invention of Busk.

11. A Water Screw

Illustrated by the invention of Ericsson.

Besides the above plans, which are applicable to steam navigation in general, others have been proposed for the navigation of canals and shallow rivers, some of which we shall notice.