MERCANTILE STEAM TRANSPORT ECONOMY. 431 



in the weight of cargo which these ships of (say) 2500 tons displacement, 

 with mean quantity of coal on board, would respectively carry on a given 

 passage, if powered for running at the speed of 8, 10, and 12 knots per hour. 

 For this exposition we will assume the weight of the ships themselves, as 

 measured by the light displacement of ships, when ready to receive cargo and 

 coal for the voyage, to appropriate 1000 tons displacement, being 40 per 

 cent, of the load displacement. We will also assume the weight of the 

 engine department complete at 5 cwts. per ind. h. p., and the consumption of 

 coal to be at the rate of 4 lbs. per ind. h.p. per hour, and the length of passage, 

 without re-coaling, to be 3250 nautical miles, being about the distance from 

 Liverpool to New York, or to Constantinople. On these data, according as 

 the vessels may be powered, as before shown, for being propelled at the speed 

 of 8, 10, and 12 knots per hour, the displacement available for cargo in A 

 will be 1270 tons, 1103 tons, and 875 tons weight of cargo ; while in B it will 

 be 1152, 900, and 556 tons weight. The consumption of coal in A will be 

 273 tons at 8 knots, 427 tons at 10 knots, and 615 tons at 12 knots ; and in 

 B it will be 412, 64^5, and 929 tons weight. Hence it appears that purely in 

 consequence of the difference in constructive type, or working condition of 

 the ships, the reduction of cargo in B, as compared with A, will be 9, 18, and 

 36 per cent., according as the speed may be, 8, 10, or 12 knots per hour; 

 while the increase of coal, being in proportion to the increase of power, will 

 in each case be 50 per cent. But the public evils of an inferior type, or 

 neglected condition of ships, will be still more fully exposed, and be more 

 definitely understood by the extra £ s. d. charge that must be made for 

 freight per ton weight of goods conveyed, in order to meet the prime cost 

 expense of conveyance. In order to work out this calculation, we must 

 assume certain data of investment and current expense as constituting the 

 prime cost charges of permanently establishing and upholding a commercial 

 fleet of steam-ships ; and as this is the vital point in which the public, as con- 

 sumers, have a direct interest, it will be expected that I enter upon it in con- 

 siderable detail, as set forth in Supplement to ' Steam-ship Capability,' 2nd 

 edit, page 76. 



In the first place, I would remark that it is only during the number of days 

 that steamers are annually at sea conveying cargoes of goods from port to 

 port that they earn the income that is to defray the whole annual expenditure 

 incurred. The number of days per annum during which steamers are at sea 

 will, of course, depend materially on the service in which they may be 

 employed ; and as it is proposed to work out our calculations with reference 

 to a passage of 3250 nautical miles- — such, for example, as the passage from 

 England to New York or to the Black Sea — I have assumed that the vessels 

 employed on such service may be at sea 200 days per annum. In the next 

 place, the cost of coal is a very material item, greatly dependent on the 

 service on which the vessels may be employed. This I have assumed at £2 

 per ton weight as the average cost of the yearly consumption. Next, as to 

 the ship ; I have assumed that a ship of 2500 to 3000 tons load displacement 

 would be purchased from the builders as a ship of about the same amount of 

 tonnage, builders' measurement, and that the cost of the ship, completely 

 fitted, equipped, and furnished in all respects ready for sea, would be £25 per 

 ton. Then, assuming the interest on investment at £5 per cent, per annum, 

 the upholding and replacement at lOper cent, per annum, insurance at 5 per 

 cent, per annum, and wages and rations of officers and crew all the year 

 round at £3 per 100 tons per week ; on these data we shall have the prime 

 cost expenses incidental to the hull amounting to £6 \\s.2d. per ton of 

 tonnage per annum, which is Sd. per day sea-time, assuming the vessel to be 



