124 REPORT — 1859. 



Mercantile Steam Transport Economy as affected by the Consumption 

 of Coals. By Charles Atherton, Chief Engineer, Royal Dock- 

 yard, Woolwich. 



Public usefulness, as dependent upon science, being the great object for which 

 the " British Association for the Advancement of Science " was originated, 

 and has now been signally upheld for twenty-nine years, a period remarkable 

 for the progress that has been made in the utilization of the powers of nature, 

 to such an extent that the international condition of the globe is now being 

 revolutionized by the progressive practical utilization of elements which 

 heretofore were regarded merely as phenomena of nature, viz. Steam and 

 Electricity; in which revolution the application of steam to the purposes of 

 navigation has played so conspicuous a part, that now, in proportion as 

 steam may be effectively employed in the pursuits of commerce and of war, 

 it is acknowledged that even nations will rise or fall ; seeing, moreover, that 

 at no period in the history of steam navigation has so great a step been made 

 in its practical development as has recently been realized by the fearless intro- 

 duction, in marine engineering, of the long known but neglected effects of 

 increased pressure, superheating, and expansion ; the recognition and appli- 

 cation of which principles have now, at length, been attended with such effect 

 in marine engineering, that the consumption of fuel with reference to power 

 is now known to be practically reducible to less than one-half of the ordinary 

 consumption of coal on board ship ; — seeing also that mercantile enterprise, 

 setting no limit to speculative investment, has in these days emancipated 

 mechanical intellect from the restrictions by which ideas as respects magni- 

 tude have hitherto been bound ; — under such circumstances I cannot doubt 

 that any effort to popularise a knowledge of the practical utilization of 

 steam, with reference to the consumption of fuel, though advanced with no 

 pretensions to science, beyond that which may be awarded to originality and 

 labour in the application of calculations to develope useful results, will be 

 favourably received, more especially as the paper which I now beg to present 

 is in continuation and conclusion of an inquiry, which has already, in part, 

 on two occasions been favourably entertained by this Association, and 

 honoured with a place in its published records. The former papers to which 

 1 allude are, — 1st, " Mercantile Steam Transport Economy, with reference to 

 Speed," vol. for 1856, p. 423 ; 2nd, "Mercantile Steam Transport Economy, 

 with reference to the Magnitude of Ships, and their Proportions of Build," 

 vol. for 1857, p. 112. And I now purpose to bring this inquiry to its con- 

 clusion by the following paper on — 



Mercantile Steam Transport Economy, as affected by the Consumption of 

 Coals.- — My purpose, and the drift of my remarks will probably be the more 

 readily understood by my at once adducing the following Tables C and D, 

 and the diagram E, in continuation of the Tables A and B, which are pub- 

 lished in the Volume of Reports for the year 1857, pp. 116 and 119, 

 observing with reference to these Tables C and D, that the rate of consump- 

 tion of coal on which the calculations arc based, viz. 2| lbs. per indicated 

 horse-power per hour, has been practically realized on continuous sea service, 

 although the ordinary consumption of steam-ships in the Royal Navy, as well 

 as in the best vessels of the most celebrated steam-shipping companies, is, I 

 believe, at the present time fully 50 per cent, in excess of that amount ; and 

 I may say, that in steam shipping generally, the consumption of coals per • 

 knot of distance, with respect to displacement and speed, is double the con- 

 sumption which these Tables, based as they are on an example of existing 

 practice, show to be now practically realizable. 



