ON FREIGHT AS AFFECTED BY DYNAMIC PROPERTIES. 89 



the speed of 10 knots an hour), by increasing the consumption of coal from 

 2 lbs. to 4 lbs. per indicated horse-power per hour, the expense per ton of 

 goods conveyed becomes increased in the proportion of 49 to 56, that is, in 

 the proportion of 100 to 114, being an increase of 14 percent., or, assuming 

 the freight by the standard ship A, consuming 2 lbs. of coal per indicated 

 horse-power per hour, to be at the rate of £1 per ton of cargo conveyed, the 

 rate of freight by ship C^, consuming 3 lbs. per indicated horse-power per 

 hour, will be £1 Is. '2d., being an increase of 6 per cent., and the rate of 

 freight by ship C^, consuming 4 lbs. per indicated horse-power per hour, will be 

 £\ 2s. \0d., being an increase of 14 per cent, per ton of goods conveyed 

 under the conditions referred to. 



The comparative freight charges on 100,000 tons of goods by the vessels 

 A, C,, Cj, respectively would be £100,000, £106,000, and £114,000. 



Section D. — Freight charge as affected (cteteris parihvs) by variations in 

 the constructive weight of hull with reference to the size of the ship as de- 

 termined by the load displacement. 



To illustrate this matter it has been assumed that the weight of hull, 

 including the whole equipment complete for sea (exclusive of engines, coal, 

 and cargo) may vary from 40 per cent, of the load displacement to 60 per 

 cent., under which limitations, by reference to table (Section D), it appears 

 that, under the special conditions of the service underjconsideration, by in- 

 creasing the weight of hull from 40 per cent, of its displacement to 60 per 

 cent., and assuming the cost of the hull to be in proportion to its weight of 

 materials, the expenses or freight charge per ton of cargo conveyed become 

 increased in the proportion of 49 to 120, that is, in the proportion of 100 to 

 245, being an increase of 140 per cent., or, assuming the freight charge by 

 the standard ship A, of which the weight of hull is 40 per cent, of the load 

 displacement (2000 tons) to be at the rate of £1 per ton of goods conveyed, the 

 rate of freight by ship T)^, of v/hich the weight of hull is 50 per cent, of the 

 load displacement (2500 tons), will be £1 10s. Id, per ton, being an increase 

 of 53 per cent., and by ship Dj, of which the weight of hull is 60 per cent, 

 of the load displacement (3000 tons), the rate of freight becomes £2 9s. per 

 ton, being an increase of 145 per cent, per ton of goods conveyed under the 

 conditions referred to. 



The comparative freight charges on 100,000 tons of goods by the vessels 

 A, Dj, D,, respectively, would be £100,000, £153,000, and £245,000. 



Hence,in the construction of steam-ships we see the importance of quality of 

 material and excellence of fastening as a means of reducing weight, and the dis- 

 advantage that attends heavy-built ships, such as war-steamers, for discharging 

 mercantile service. Hence also we see the deficient steaming endurance or 

 limited armament of high-speed armoured ships unless built of enormous 

 size, as measured by their load displacement, and the disadvantage of types of 

 form which require the aid of ballast to insure stability. 



Section E. — Freight is affected (cceferis paribus) by variations in the 

 constructive type of form combined with variations in the working economy 

 of the engines. 



By reference to the Table (Section E), it appears, under the special con- 

 ditions of the service under consideration, that by an inferior type of form, as 

 indicated by the coefficient of perlormance being reduced from 250 to 1.50, 

 combined with an inferior construction of engines, as indicated by the con- 

 sumption of fuel being increased from 2 lbs. to 4lbs. per indicated horse-power 

 per hour, thereby reducing the coefficient of dynamic duty (column 7) from 

 14,000 to 4200, the expense or freight charge per ton of goods conveyed 

 becomes increased in tfie ratio of 100 to 179, being an increase of 79 per 



