axle, with a hole to communicate therewith; the lubricating matter was, therefore, constantly in contact with the axle; and when the latter became in the least degree heated, for want of oil, the heat produced a fresh supply. Mr. Booth has a patent for a kind of lubricating substance of this description, which consists of a solution of the common washing soda of the shops, in the proportion of half a pound of the salt to a gallon of pure water; to one gallon of this solution, three pounds of good clean tallow, and six pounds of palm oil are added; or, instead of the mixture of palm oil and tallow, ten pounds of palm oil, or eight pounds of firm tallow. The whole mixture is heated to about 200° or 210° of Fahr., and well stirred, or agitated, until the composition is cooled down to 60° or 70° of Fahr., and has obtained the consistency of butter, in which state it is ready for use.

The kind of bearing, previously described, is used where the wheels are on the outside of the frame-work of the carriage, or where the bearing is on the inside of the wheels. In many carriages, and especially those for the conveyance of bulky goods, it is necessary to have a greater width of frame-work, than that which can be obtained within the wheels; and, hence, it is necessary to elevate the frame-work of the carriage above the wheels, and increase its width; in which case the bearings are placed on the outside of the wheels. Independently of the increased accommodation which such a form of carriage presents, there are other considerations, which make a bearing outside the wheels, preferable to one within the wheels. In the latter case, the size of axle is necessarily large to resist the shocks, as well as the direct weight of the load; and when the wheels are of large diameter, the twist upon the axles is very considerable. With inside bearings, therefore,

the chair, or semicircular bearing, cannot be of less diameter than the size of the axle; but outside bearings not being subject to the twisting of the wheels, the diameter of the axle, at the bearing, can be made much less; and, if we suppose the same resistance acting on the surfaces in both cases, the friction should be in the direct ratio of the diameter of the axle at the points of bearing, and, consequently, greater with the inside than outside bearing. Carriages carrying about four tons of goods, and with three-feet wheels, require axles, at least, three inches and a quarter in diameter, which must be the size of the bearings inside the wheels; whereas the outside bearings may be reduced to two inches, and thus diminish the resistance considerably.

Figs. 5, 6, and 7, Plate VII., shew a plan of axle and bearing on the outside of the wheels; a is that part of the axle, on which the nave of the wheel is fixed; bb, shewing a part of the nave, and c the end of the axle, which constitutes the bearing portion; in this bearing, the axle diminishes in diameter in three divisions. Fig. 8, is another plan, which is more generally adopted, than the preceding. Fig. 6, shews a section of the bearing, or chair, through the middle; this chair consists of a cast-iron box, 1, 2, 3, 4, in two pieces, separated at 4', and fastened together by bolts, the holes of which are shewn at 5, 6, on the plan Fig.7; one of the bolts is shewn by the dotted line, d, Fig. 6. The extreme end of the axle, it will be seen, is increased in diameter, for the purpose of preventing the chair from sliding outwards, and, therefore, it necessarily causes the chair to be made in two pieces; ie, ie, are the upper lower brass parts, which rest on the axle, and surround it, and which are enclosed by the cast-iron chair, 1,2,3,4. A cavity, or chamber, at f, is cast in the chair, to con

and

tain the oil, or other lubricating matter, which, in the middle, is open to the to the upper side of the brass bearing; the oil being communicated to the axle by the two holes, shewn in the drawing. This chamber is covered, at the top, by a lid, 2 g, by which it can be filled with oil at any time. The spring, shewn at g g, Figs. 6 and 7, rests upon the chair, and is fastened to it by the same bolts which fasten the chair together, as shewn at g d, Fig. 6. Fig. 7, which is a plan of the bearing, shews the spring, g g; 5 and 6 being the bolt-holes for fastening the chair together, and also fastening the spring upon the chair. The middle compartment is the chamber, which contains the oil, with the hole through the brass of the chair, to lubricate the axle; the two side compartments, shewing that part on which the springs rest, with the bolt-holes, for fastening the springs to the chair. Vertical guides, similar to those shewn at ff. Fig. 10, are fastened to the side of the frame of the carriages; and the grooves, hh, Fig. 7, are cast for the guides to work in. Fig. 9, shews a plan of bearing, used on the carriages for the Newcastle and Carlisle railway, and is a vertical section, through the middle of the chair; e, being the upper side of the brass, and e', the under part. This chair is put together in two parts, meeting in the middle of the axle, and bolted together by two bolts on each side, as shewn at 1 1, Fig. 4. In this bearing, the spring does not rest upon the back, or upper side of it, as in Fig. 6; but the spring is placed above the frame of the carriage, as shewn in Fig. 10, with a bolt, 2', passing through the frame, and resting on the upper side of the chair, by which the spring is acted upon by the inequality of the road. This bolt, resting upon the middle of the chair, prevents the possibility of a chamber in the middle for the oil, and there are, therefore, two chambers for that purpose,

one on each side of the part whereon the bolt rests; with two holes, 1 1, communicating with the brass of the bearing, and axle, for the oil to pass to the bearing part of the axle.

In the plan of bearing, Figs. 6 and 7, the guides are fastened to the outside of the framing of the carriage, and work within the grooves, hh, Fig. 7. In the plan, Fig. 9, the guides are made nearly the whole breadth of the chair, and work within the projecting parts, 33, 44, of the chair, Fig. 4. ff, Fig. 10, shew this plan of guides; one cheek of the guide, shewn by the dotted lines, projects upwards, on the inside of the frame, to steady it; and it is bolted upwards to the frame, by the bolts, a a, a a. The dotted lines, 3 3, 4 4, Fig. 9, represent the cheeks of the chair, within which the guides slide up and down; that part of the bearing on each side, projecting a little, as seen at c, in Fig. 10, and effectually acting as a guide for the chair to slide up and down. To secure the stability of the carriages, and counteract the twisting of the framing at the curves, it is very important, that the guides should be fixed, so that no working should take place, in the oscillation of the carriages, from one side to the other. Besides the bolts, cc, a stay, b, on each side, also passes between each guide, with a cross bolt between each sidestay, at b; a diagonal stay at each end, at dd, is also placed to steady the guides, and which likewise acts as braces to support that part of the framing of the carriage, which projects beyond the wheels.

The springs in Fig. 10, it will be seen, are placed above the frame of the carriage; that is done for the purpose of keeping the platform of the carriage as low as possible. If the springs were placed below the framing, or were made to rest upon the chair, as in Fig. 6, it would raise the frame, 4 4, so much higher, as would

be equal to the thickness of the spring. Another disadvantage of having the spring below the frame, is, that it increases the depth of the guides; and, of course, renders them weaker in resisting the side shocks, or twisting of the curves.

The bolt, 2, Fig. 9, passes through a hole in the frame of the carriage, and rests against the under side of the middle of the spring.

On all these bearings, it will be seen, that the end of the axle is increased in size, or that a collar is laid around the axle, so as to make it larger in diameter, than that part whereon the chair rests; this is done for the purpose of steadying the guides, or to prevent them from extending outwards, or in breadth. This has been found to be quite necessary, as some were tried upon the Newcastle and Carlisle railway without this collar, the guides and chairs of which, could not be kept at the proper width. We may here remark, that all these bearings are upon the principle of the wheels being fixed to the axle, and turning with them; which is the reverse of what is universally used on the carriages upon turnpike roads, where the wheels turn round upon the axle. In railway carriages, however, the depth of the flanch, to keep the wheels upon the rail, is only one inch; and it is necessary that no vibration of the wheel should exist, otherwise its liability to get off the rail would be greatly increased. In all bearings, similar to those used on common roads, some vibration exists, especially when they are a little worn; and the following trial will shew that the least vibration is injurious :-On the Newcastle and Carlisle railway some carriages were constructed, with the axles fitted into the nave of the wheel, in the same way as if they were to turn round with the wheels; except that, instead of the axles being keyed to the nave of the wheel at both ends, one of the wheels on each