Under the carriage attached to the framing are four reservoirs, holding about three and a half cubic feet of water, of which water space one-half acts as a reservoir for cold feed water, and half for the condensed water. A tube from the small reservoir on the engine communicates through valves with the reservoirs of hot and cold water on the carriage. The consumption of cold water measured during two days was 2.86 lb. per kilometer; assuming that the boiler evaporated 6.5 lb. of water per pound of coal, the cold water formed one-fifth of the total feed water required. The carriage, i. e., the part occupied by passengers, is 21 ft. 8 in. in length. It holds seats for forty-five passengers, besides those who would stand on the gangway and platform. The seats are placed transversely on each side of a central corridor, each seat holding two people. The platform of the carriage is about 2 ft. 6 in. above the rails. Passengers have access to the interior from behind by means of the end platform, and in front near the engine from the two sides. As already mentioned, the hind part of the carriage rests upon two wheels, the front part being, as already mentioned, supported on the engine bogie. To effect this support, the hinder part of the framing of the engine is formed in a half circle, with a broad groove, in which the ends of two springs are arranged to slide. The centers of the springs form the support of the framing of the carriage. The framing of the engine bogie is attached to the hind bogie truck of the carriage by two diagonal drawbars. The coupling is effected by bolts close to the engine, and the car is drawn entirely by means of the bogie pin of the hind bogie. The trucks are 16.5 ft. apart. Table I. above shows the dimensions of different parts of these three steam motors, as well as their weights. The Beaumont engine, worked by compressed air, may be generally said to be similar to that described in a paper read before the Society of Arts on the 16th March, 1881, to which, however, some improvements have been since introduced. The apparatus for compressing the air was placed in the shed. The air was compressed to 63 atmospheres by a pump worked by a steam engine, and stored in cylindrical reservoirs of wrought iron without rivets. A pipe led the air from the reservoirs to the head of the tramway, where the cylinder placed on the motor for storing the air during the journey could be conveniently charged. The air was compressed by means of four pumps, placed two and two in a water-box, and worked by the direct action of a compound engine, with cylinders, placed in juxtaposition, of 8 in. and 14 in. diameter respectively, with an equal length of stroke of 13 in. TABLE I.