MERCANTILE STEAM TRANSPORT ECONOMY. 423 



Mercantile Steam Transport Economy. By Charles Atherton, 

 Chief Engineer of Her Majesty's Dockyard, Woolwich. 



[A Communication directed to be printed entire among the Reports of the Association.] 



The construction of ships and the administration of shipping affairs, invol- 

 ving a multiplicity of considerations of a scientific and of a practical and 

 mercantile character connected with these arts, requires that shipping direc- 

 tion be regarded and treated as the subject of an exclusive science; and, of 

 late years, the progressively extended application of steam to maritime pur- 

 poses, and the prospect of its general use as an auxiliary power, have still 

 further complicated the subject, and extended the range of mercantile 

 acquirement which is now necessary in the prosecution of steam-ship equip- 

 ment, direction, and management. It is therefore with diffidence, and with 

 the feeling of my not possessing the combination of qualifications which is 

 necessary to ensure adequate justice being done in all respects to the eluci- 

 dation of the important subject, " Steam Transport Economy," that I enter 

 upon the task of bringing that subject before the notice of the British Asso- 

 ciation for the Promotion of Science. I am, however, encouraged by the 

 assuring reflection that public utility is a field in which it is an honour to 

 labour, that lenient consideration for individual deficiencies and the helping 

 hand of others will be extended to the most humble delvers in that field, and 

 that credit may be earned in proportion to the roughness and obdurate nature 

 of the spot of ground which we may have undertaken to break up, and to 

 the perseverance by which one may at least attempt the accomplishment of 

 the assigned task. Permit me, therefore, to remark, that uiy present appeal 

 to the British Association is but a continuation of my previous efforts in the 

 cause of steam exposition, with a view to bringing " Steam Transport Eco- 

 nomy " within the pale of arithnietical calculation ; and as I shall have occa- 

 sion to refer to the enunciation of principles and to the details of calculations 

 which have thus preceded this essay, it may be convenient that I briefly 

 enumerate the various published statements thus referred to as forming an 

 integral portion of this paper, and which, accordingly, I beg to hand in to 

 the Association for the purposes of reference and record. 



1st. A brief essay on ' Marine Engine Construction and Classification,' 

 published by Weale, in 1851. 



The object of this essay was to analyse the data afforded by published and 

 authentic statements of the actual test-trial performances of various steam- 

 ships, and ascertain, by means of such comparative analysis, what are the 

 peculiarities or proportions of build, and what are the peculiarities of engine- 

 construction of those vessels which have attained to the highest degrees of 

 locomotive efficiency, thereby also scrutinising how far the popularly re- 

 ceived notions in regard to steam-ship type and marine engine construction, 

 supposed to be most conducive to locomotive efficiency, may be in accord- 

 ance with, or in opposition to, the results of actual experience, when mea- 

 sured by any definite and received law. 



2nd. An essay on ' Steam-ship Capability,' originally published in 1853, 

 and of which a second edition, with supplement, was published by Weale, in 



1864.. 



This essay was designed to demonstrate the mutual relations which subsist 

 between displacement, power, and speed in steam-ships ; especially as respects 

 the increasing scale of engine-power by which progressive increase of speed 

 is attained ; and to show the diflSculties which attend the prosecution of a 

 steam service in which long passages are required to be performed at a high 



