In the Servia the machinery consists of three cylinder compound surface condensing engines, one cylinder being 72 inches, and two 100 inches in diameter, with a stroke of piston of 6 feet 6 inches. There are seven boilers and thirty-nine furnaces. Practically the Servia is a five decker, as she is built with four decks--of steel, covered with yellow pine--and a promenade reserved for passengers. There is a music room on the upper deck, which is 50 feet by 22 feet, and which is handsomely fitted up with polished wood panelings. For the convenience of the passengers there are no less than four different entrances from the upper deck to the cabins. The saloon is 74 feet by 49 feet, with sitting accommodations for 350 persons, while the clear height under the beams is 8 feet 6 inches. The sides are all in fancy woods, with beautifully polished inlaid panels, and all the upholstery of the saloon is of morocco leather. For two-thirds of its entire length the lower deck is fitted up with first class staterooms. The ship is divided into nine water-tight bulkheads, and she is built according to the Admiralty requirements for war purposes. There are in all twelve boats equipped as life-boats. The Servia possesses a peculiarity which will add to her safety, namely, a double bottom, or inner skin. Thus, were she to ground on rocks, she would be perfectly safe, so long as the inner skin remained intact. Steam is used for heating the cabins and saloons, and by this means the temperature can be properly adjusted in all weathers. In every part of the vessel the most advanced scientific improvements have been adopted. The Servia leaves Liverpool on October 22.

The Alaska, whose owners, it is understood, are determined to make her beat all afloat in speed, does not sail until November 5, and therefore it is premature to say anything about her interior equipments. She is the sister of the celebrated Arizona, and was built by the well-known firm of Elder & Co., on the Clyde.


IMPROVED ROAD LOCOMOTIVE.

Several attempts have been made to connect the leading wheels of a traction engine with the driving wheels, so as to make drivers of all of them, and thus increase the tractive power of the engine, and to afford greater facilities for getting along soft ground or out of holes. The wheels with continuous railway and India-rubber tires have been employed to gain the required adhesion, but these wheels have been too costly, and the attempts to couple driving and leading wheels have failed. The arrangement for making the leading wheels into drivers, illustrated on page 4825, has been recently brought out by the Durham and North Yorkshire Steam Cultivation Company, Ripon, the design being by Messrs. Johnson and Phillips. The invention consists in mounting the leading axle in a ball and long socket, the socket being rotated in fixed bearings. The ball having but limited range of motion in the socket, is driven round with it, but is free to move in azimuth for steering.

This engine has now been in use more than twelve months in traction and thrashing work, and, we are informed, with complete success. The illustrations represent a 7-horse power, with a cylinder 8 in. diameter by 12 in. stroke, and steam jacketed. The shafts and axles are of Bowling iron. The boiler contains 140 ft. of heating surface, and is made entirely of Bowling iron, with the longitudinal seams welded. The gearing is fitted with two speeds arranged to travel at 1½ and 3 miles per hour, and the front or hind road wheels can be put out of gear when not required. The hind driving wheels are 5 ft. 6 in. diameter, and the front wheels 5 ft.; weight of engine 8 tons.--The Engineer.

IMPROVED ROAD LOCOMOTIVE