The Century of Inventions of the Marquis of Worcester / from the Original MS., with Historical and Explanatory Notes and a Biographical Memoir

by Marquis of Edward Somerset Worcester

The valve B in this case rests upon a conical seat in the boiler A, and is furnished with a series of small moveable plates lettered c, which are employed to increase or diminish the entire weight of the safety-valve, the whole being covered by the box D; and as this is pierced with a number of small holes, the steam readily escapes when the expansive force exceeds the resistance offered by the loaded valve.

The patent revolving wheel invented by Mr. Masterman, appears to promise the best results of any rotatory engine yet invented, the friction being much less than in any other apparatus in which steam is employed as a prime mover. In this engine, Mr. Masterman proposes to employ water, or the fluid metal mercury as the immediate agent, which he effects by inclosing it in the tubular rim of a large wheel, furnished with valves opening in one direction. This wheel, as is shewn in the opposite diagram, is made to revolve on a hollow axis connected with the steam boiler. The arms or spokes which radiate from the axis are also hollow; and on the admission of steam from the boiler, it is conducted through the arm immediately opposite, and entering the rim of the wheel, comes in contact with, and presses against the column of water beneath and the closed valve above the arm. The water being previously heated to the boiling point, no condensation ensues, but the whole weight of water, which was previously balanced in two columns of equal height, is driven, by the pressure of the steam, to the side opposite to that at which the elastic vapour entered, and that side of the wheel will necessarily preponderate. If this process be repeated, the steam being allowed to blow through each radiating arm in succession, a continuous rotatory motion will be produced. Should it be advisable to employ steam of less elasticity, a condenser may be added, and that too without materially increasing the expense.

The application of steam-engines to the propelling of carriages on the public road, has hitherto been considered as a refinement in mechanics, rather to be wished for than a matter of reasonable expectation. The locomotive engine was first employed for this purpose by Messrs. Trevithick and Vivian, in 1802; and it found a ready introduction to the mining districts where rail-roads are general. In some cases, five, six, and even ten waggons laden with coal are dragged up an inclined plane by means of these vehicles; and of course impelled by a high pressure engine, from the utter impossibility of carrying condensing water in a moveable vehicle.

An engine of four horses' power, employed by Mr. Blenkinsop, impelled a carriage lightly loaded on a rail-road at the rate of ten miles an hour, and when connected with thirty coal waggons, each weighing more than three tons, its average rate was about one-third of that pace.

When the locomotive engine was first tried, it was found difficult to produce a sufficient degree of re-action between the wheels and the tract road; so that the wheels turned round without propelling the vehicle. This inconvenience was, however, obviated by Mr. Blenkinsop, who, when he adopted the locomotive engine, took up the common rails, on one side of the whole length of the road, and replaced them by a series of racks, or rails, furnished with large teeth. The impelling wheel of the engine was made to act in these teeth, so that it continued to work in a rack which insured a sufficient degree of re-action.

From the great weight of an ordinary locomotive engine as well as the construction of its impelling wheel, it must be evident that the employment of this species of prime mover on the public roads would be in the highest degree destructive; and as such that its use will for some years to come be partially confined to the mining districts, in which the greatest facilities are offered for its general adoption. Indeed, we find in one neighbourhood alone, and within a space of less than thirty square miles, more than twenty miles of road admirably adapted for this species of conveyance; and it is a well known fact, that there are many situations in which iron rail-roads might be advantageously employed, in which it would be quite impossible to open a navigable canal. In illustration of the above fact, it may be proper to state, that a company, with a large capital, is now forming for the express purpose of facilitating the conveyance of goods by locomotive engines.

The mode of applying the steam-engine to the purposes of navigation is equally simple with its employment in our manufactures.

It is generally supposed that the steam-boat is of very recent invention; on the contrary, however, the possibility of employing steam as a prime mover in the propelling of vessels was suggested as far back as the reign of Charles I.