“The funnel also,” says the _Illustrated London News_ of May 12, 1849, in describing the vessel, “is to have some peculiar mode by which its hideous and crater-like physiognomy can be made at once to disappear, and leave the ship devoid at once of this unsightly feature, and of those cumbrous excrescences, paddle-boxes, giving her all the appearance and symmetry of a perfect sailing-ship.” She carried ten 32-pounder muzzle-loading guns. Her machinery is of special interest as it embodied one of the earliest attempts to drive a screw propeller by gearing. For this purpose it had four sets of massive spur wheels and pinions, in the ratio of 2.35 to 1, so that 42 revolutions of the engines per minute gave 98.7 revolutions per minute to the propeller shaft. The engines installed in steamers, whether for war or commerce, were of the side-lever type, until they were superseded by the direct-acting type. The former was peculiarly suitable to the paddle-wheel, and in one form or another is in use to the present day. In America, the practice has been to place the beam or lever above the crank, but on this side of the Atlantic the beam was placed below the crank. So far as warships were concerned, this method had the advantage that a great part of the machinery could be placed low down in the vessel. But the very fact that a vessel was propelled by paddle-wheels made it impossible to place the whole of the engine below the water level; it is evident that the greater the diameter of the side-wheels the greater must be the distance between the surface and the crank or shaft upon which the wheels are fastened for rotation. As increased power was required, it became necessary to add to the size and weight of the engines, which in this respect soon reached the profitable limit of their employment. Engineers were not long in foreseeing the extent of the difficulty, and, in seeking means to provide a smaller engine without loss of power, discovered a method of eliminating the lever and causing the engines to act direct upon the crank shaft. One very ingenious method by which the desired result was accomplished was that associated with the name of Mr. Penn, who introduced the oscillating cylinder in 1836. In these engines the connecting rod is done away with altogether, the piston rod works directly on the crank pin, and the cylinder is carried on trunnions which permit of the necessary oscillation, and are themselves made hollow in order that the steam may be admitted to and exhausted from the cylinders through them. The first Admiralty vessel in which they were fitted was the yacht _Black Eagle_. Another method by which great economy in space was effected was the double cylinder engine invented by Messrs. Maudslay. It consisted of two cylinders of equal size placed side by side, but with a space between them into which the foot of a =T=-shaped cross-head passed, the foot of the =T= head being connected by a connecting rod with the crank pin.