In this table a very great difference of cost will be observed, between the conveyance of coals, and general merchandize; the latter amounting to 2.138d. per ton, per mile, while the average of the former is 1.315d. per ton, per mile. This arises from several causes. On public railways, for general merchandize and passengers, when the latter is conveyed at a high rate of speed, it is almost, if not entirely unavoidable, to prevent the trains with goods partaking, to a certain extent, of a rate of speed beyond that of the most economical; the trains are likewise obliged to be set off, at certain stated periods, whether they are fully loaded or not. We see that the trains, with general merchandize, upon the Liverpool and Manchester railway, from which the above cost is deduced, average only 47.2 tons gross load; upon the Stockton and Darlington railway the average load is 63-6 tons; the former travelling at the rate of twelve to fifteen miles an hour, and the latter eight to ten miles an hour. On a reference to § 4, Art. 7, Chap. IX., it will be seen, that the relative economy of these engines travelling at different rates of speed, and with loads proportioned to the rate of speed, is in the ratio of the resistance of the gross load taken, including the engine; the relative resistances of these loads will be as 66: 83. The cost of conveyance on the Stockton and Darlington railway is 4d. per ton, per mile; therefore, as 4 66: : 83: 5, which is nearly the cost of the Liverpool engines.

The above calculation will account for the increase of expense of the motive power; but this only amounts to •125d. per ton, per mile, whereas the difference is '873d., leaving 748d. per ton per mile not accounted for. We observe, that the expense of carriages is greater for general merchandize than for coals and minerals; but the great difference exists in the expense of conducting

the traffic of general merchandize upon public railways, in receiving and storing, loading and unloading goods, and in the expense of the necessary attendants; none of whom are required for coals and minerals, which are generally loaded and unloaded by the proprietors. The expense of conducting the traffic, including the above enumerated charges, amounts to 1d. per ton, per mile, upon the goods, actually subject to the above charges; or 460d. per ton, per mile, upon the aggregate traffic on the Liverpool and Manchester railway. This expense, together with several other items, which will be seen on examining the particulars under the respective heads of charge, incidental to a public railway, with a mixed traffic; will account, satisfactorily, for the difference between the cost of conveying merchandize on such railways, and coals or minerals on railways more particularly applicable to the conveyance of such articles.

It is, however, a question of some importance, how far public railways, with a mixed traffic, and on which passengers are to be conveyed at high rates of speed, are applicable to the economical conveyance of heavy goods or minerals. We have before remarked, that the example of the cost of the Liverpool and Manchester railway, must be taken as being beyond what may reasonably be expected to be the cost of future railways. Taking, however, the cost of that railway, we find the expense of motive power 55d., of maintenance of the railway 307d., and the cost of upholding waggons 227d., altogether 1·084d. per ton, per mile. These are the direct expenses, any traffic on which dues above these sums can be charged, will operate to diminish the general or constant expenses of the establishment, and will, therefore, be profit, with the exception of a portion of expense of attendants, &c.; if we take the general

charges the same as upon the Stockton and Darlington railway, or at 100d. per ton, per mile, we have the whole expense equal to 1.184d. per ton, per mile.

We see, therefore, that the entire cost of conveying minerals or coals along a public railway, with a mixed traffic, will be 1.184d. per ton, per mile; without reckoning any charge for interest of capital, or profits, and taking the expense of the Liverpool railway as a standard; and if we take the contract price for haulage, upon the London and Birmingham railway, this will be reduced to 1.134d. per ton per mile. We have already explained, that the expense of the motive power is increased by the diminished load taken at each trip, that the cost of maintenance of the Liverpool railway is greater than may be expected in future; we may, therefore, state, generally, that the direct expenses, exclusive of loading and unloading, and of conveying coals or minerals along public railways, will amount to about 1d. per ton, per mile; and that any charge beyond that, will assist in reducing the general expense of the necessary establishment of the railway, for conducting the other traffic.

CHAPTER X.

COMPARISON OF THE DIFFERENT DESCRIPTIONS OF MOTIVE POWER ON RAILROADS.

§ 1.-Horses and Locomotive Engines.

WE shall now endeavour to shew the relative performances of horses, and locomotive engines, on railroads; and, in doing so, we shall place them in contrast with each other, at three different rates of speed, viz., 1st, That when with regard to horses, their performance with the load may be considered a maximum, or at 21⁄2 miles an hour; 2d, That when travelling, with light carts, at the rate of four miles an hour; and, 3d, That when travelling at the greatest rate of speed, which they are capable of doing, when yielding any available power to the load.

With regard to locomotive engines, the rate of speed in each of these divisions will greatly exceed that of horses; but still the comparison will, in some degree, hold good, as, with those engines, we have their performance with heavy loads, at from six to eight miles an hour; with merchandize, at from twelve to fifteen miles an hour; and, with passengers, at upwards of twenty miles; or, in each of the three cases, a little beyond double the rate of speed of horses.

In the former edition of this Work, we confined ourselves to a comparison of the relative performances of horses and locomotive engines, only with respect to the quantity of work which each was capable of performing; this comparison, however, did not comprehend the

whole question, and was, in some respects, objectionable, In the first place, scarcely two locomotive engines are of precisely the same power, and, therefore, in fixing upon a standard whereby to compare with the power of a horse, it will depend entirely upon the power of engine we fix upon, to compare with horses, what number of horses' work such an engine is capable of performing; and although the comparison might be useful, as shewing the relative capabilities as to the mechanical effort, of the two descriptions of motive power, it would not be productive of any useful purpose, in practice.

The sole object of the employment of both these modes of transport is, to convey goods, or passengers, and the rate of speed and cost at which they can be conveyed, is the great desideratum; for, although an engine may be capable of performing the work of several horses, yet the cost may be more than in proportion to the increased performance; and, consequently, unless we know the cost of each of the two systems, the information will be defective. We shall, therefore, in this edition, give the cost of conveying goods by horses, and locomotive engines, deduced from the preceding investigations. Referring to Table IX. Chap. IX. § 1, Art. 7, we have the cost of conveying goods and passengers, by horses, on railroads; and to Table XIV. § 4, Art. 8, in the same chapter, we have the cost of the same work, by locomotive engines, from which the following table has been constructed.

Art. 1.-On the comparative Cost of Horses and
Locomotive Engines.

Table of the relative cost of conveying goods, and passengers; by horses, and locomotive engines, on rail