wheels on either side of the rail in pairs, is exhibited in fig. 3, and the mode of joining the front with the hind pair of wheels, in fig. 2. Iron rings, 9 g, pass through the centres of the lower parts of the carriage-frame, to which are suspended the boxes or receptacles for holding the goods or passengers, one of which is shewn attached at h, fig. 1. The loops or holes in the upper part of the rail a, fig. 2, are, of course, for the convenience of bolting it to the suspension bars, as seen connected in fig. 1. Each of the bars is to be provided with a wedge or screw adjustment, so as to regulate the uniformity of the plane, when any part sinks.

To give an idea of the other form of rail, the section fig. 4, is sufficient. Here it will be seen, that the rail, (if we may so term it) is of the form of a square tube or hollow trunk i i, with an opening or slit on the lower side for the bar, j, (which is fixed to the axletree of the carriage) to pass through, for the purpose of being connected to a box or receptacle underneath. This square cast-iron trunk or rail, is to be suspended, as in the previously described rail, to a chain of iron bars or wires, drawn nearly tight, so as to form a catenarian curve, when stretched over the place to be crossed.

The mode of propelling the carriages is, we believe, not stated in the specification, but we understand it is to be performed, when the rail-way is on a horizontal plane, by elevating that end in which the carriages are placed, and letting them find their way to the other end by their own gravity. By such a proposition, it is evident that the patentee does not intend it for any extensive work, as the means proposed of producing motion, are applicable only to narrow rivers and ravines.

Having now noticed the three principal kinds of railways, it is very important to know the effect produced by a given power applied to each; and this knowledge has, we believe, been very faithfully furnished to the public by Mr. Palmer, who made a series of very careful experiments on several of the principal railways of the kingdom, which he published in his work before alluded to.

The results of these experiments we annex, preceded by some introductory observations of the writer on the subject.

"Perhaps," says Mr. Palmer, "if some accurate means of ascertaining the resistance of roads and railways were, on all occasions, used, their improvement would be much advanced. The real value of either being then unequivocally compared, the amount of defect could no longer be a matter of mere opinion. The proprietors would then know whether an apparent inferiority arose from the difference of horses, or difference of circumstances; and it would be of great advantage to introduce a clause in contracts, which would determine the effect to be produced. The methods by which resistance of roads and rail-ways has been ascertained, have not been sufficiently accurate, or have been too inconvenient for general use. The dynamometers, which denote the resistance by the degree of extension given to springs attached to the carriage, are convenient as portable instruments, but do not denote the mea sure with the necessary precision. The resistances are not equable from the irregularities of the surface; neither does the force which draws the carriage continue equable. When horses are employed, those instruments are of no service whatever. The effect of the unequal force or resistance occasions a vibratory motion to the indicating point, and we can never have confidence in any result they exhibit. Similar defects are observable in all the instruments I have seen.

"Having had frequent occasion to ascertain these resistances, I constructed an instrument which, by removing the imperfection referred to, has been completely successful. The problem was to make such an instrument as would indicate very small differences, but which would not yield suddenly to a change of resistance. I therefore connected to a spring dynamometer, a semicircular close copper vessel containing water; at the centre is a spindle, on which an arm or fan is fixed, and which very nearly corresponds with the inside of the vessel. The springs

are so connected with the spindle, that they cannot be acted upon without the arm or fan turning upon its centre, and passing through water. In order to pass through the water, the latter must escape by its sides; and the space being extremely small, it cannot pass rapidly, but will yield to the smallest force.

"By way of exhibiting the difference of resistance upon different rail-ways, I have attached a table containing experiments on several.

"The first column contains the articles conveyed; the second, the resistance in proportion to the weight; the third, the whole effect produced, i. e. including the weight of the carriage by one horse, or one hundred and fifty pounds, at two miles and a half per hour; the fourth, the useful effect, or the load conveyed, in pounds; the fifth, the same, in ordinary measures; the sixth, the inclination, expressed by decimal fractions, on which a rail-way, whose resistance is equal to that specified, should be constructed, that the resistance of the loaded carriages downwards, may be equal to that of the empty carriages upwards; the seventh, the effect produced under such circumstances; the eighth, the useful effect under the same, the weight of the carriages being deducted. In each experiment, the power of the horse is assumed at one hundred and fifty pounds, moving at the rate of two miles and a half per hour.

• In the inclinations, the weight of the horse itself, as part of the effect produced, is not taken into account, that the table may equally serve where mechanical force is applied. Some allowance must therefore be made, where horses are used, but the difference in the inclinations given will be very trifling.

4 F

25.

1

2

3

4

5

6

4 Cheltenham Tram Road.......

5 New Branch of ditto, slightly co-
vered with dust..

"Note.-I am indebted to Mr. GRIMSHAW, of Sunderland, for the data of No. 7."

It has, we believe, been a generally received opinion, that carriages on a rail-way cannot be propelled by locomotive power up an inclined plane that rises more than twenty feet in a mile, without the assistance of indented or toothed-rails to increase the resistance, and thus prevent the carriages from slipping back. By Mr. W. H. James's invention, this difficulty is overcome, so that a train of carriages may be made, by a locomotive engine, to ascend and descend inclined planes of any elevation necessary in the construction of rail-roads, and over very smooth and almost polished surfaces. We understand that the most satisfactory proofs have been afforded of the ability to effect this, by repeated trials on a rail-road more than a hundred feet in length, laid down for the purpose of experiment; on which it was found that a train of carriages would (with the patentee's machinery) ascend inclined planes of three inches in the yard, which is equal to four hundred and forty feet in the mile. This important advantage is gained by applying the power to the axletrees of the wheels of the several carriages in the train, by means of the rotation of a long horizontal rod (or series of connected rods) actuated by bevel gear under each carriage.

An ingenious plan has also been proposed by Mr. James for enabling the carriages on a rail-way to pass around turns or curves in the road, without additional friction. For this purpose, the horizontal rotatory shafts, which cause each pair of wheels in the train to revolve and propel the carriages forward, are connected together by a novel kind of universal joint, which communicates the rotatory motion to each successive carriage, even if so placed on the curves of the roads, that the sides of one carriage shall present to the side of the next an angle of thirty degrees. To cause the carriage wheels to run round the curves of the rail-way, without the usual destructive rubbing of their surfaces, the rails in those parts are made with several ribs or elevations, and the wheels of the carriages are consequently formed to correspond with those ribs, by their peripheries being grooved in like