ON FREIGHT AS AFFECTED BY DYNAMIC PROPERTIES. 83 



which directly affect the expenses incidental to the conveyance of merchan- 

 dise by steam-ships, and by which the rates of freight are in the aggregate 

 necessarily regulated. Freight, therefore, is the text of the following dis- 

 course, to which attention is directed under the variouc aspects of steam- 

 ship construction and management, by which freight charge is affected, and 

 which may be classified under ten heads or sections, as follow : — 



Section A. — Freight, as affected by variations of the size of the ship by 

 which the service is performed. 

 B. — Freight, as afiected by variations in the constructive type of 



form of the hull. 

 C. — Freight, as affected by variations in the working economy 



of the engines, with reference to the consumption of coal. 

 D. — Freight as affected by variations in the constructive weight 



of the hull, with reference to its load displacement. 

 E. — Freight, as affected by variations in the constructive type 

 of form combined with variations in the working economy 

 of the engines. 

 F. — Freight, as affected by variations in the size of ship com- 

 bined with variations in the constructive type of form and 

 in the working economy of the engines. 

 G. — Freight, as affected by variations of the steaming speed at 



which it is required that the service shall be performed. 

 H Freight, as affected by variations of the size of ship com- 

 bined with variations of speed. 

 I. — Freight, as affected by variations of the speed combined 



with variations of the working economy of the engines. 

 K. — Freight, as affected by variations of the speed combined 

 with variations in the type of form, working economy of the 

 engines, and weight of hull. 

 It will be observed that it is not proposed to determine the actual amount 

 of prime-cost expenses incidental to the prosecution of steam-ship enterprise, 

 by which the scale of freight charge may be chiefly regulated, but it is pro- 

 posed to demonstrate, with reference to a specified unit of performance, the 

 ratio or comparative scale of cost, in which the prime-cost expenses incidental 

 to the conveyance of cargo per ton weight of goods conveyed on a given 

 passage is, cceteris paribus, affected by each of the various circumstances or 

 conditions set fortli under the ten different heads above referred to. 



The fundamental consideration on which it is proposed to base this inves- 

 tigation is this, that, within moderate limits of variation, the investment inci- 

 dental to the fitting-out of steam-ships for commercial transport service is 

 approximately proportional to the quantity of shipping as measured by the 

 constructors' load displacement of the ships, and the amount of working- 

 power employed as measured by the indicated horse-power, also that the 

 interest on investment, upholding of stock, and all other annual expanses in- 

 cidental to the working of steam-ships, such as coals, stores, and wages, 

 harbour dues, insurance, and pilotage, are approximately proportional to such 

 investment ; and further, as the mercantile service of steam-ships employed 

 on a given station generally requires that their passages shall be periodical, it 

 is assumed in the following calculations that the number of passages made 

 annually by each ship is the same in all the different vessels assumed to be 

 employed on the same service and brought into comparison with each other. 

 It is particularly to be observed that these calculations and deductions of 

 comparative freight charges are not of general application to different 

 services, but have reference only to the special service which, as an example 



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