16 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



[Jan. 



"The imposing mechanical phenomena so rapidly and unexpectedly 

 developed by the invention and improvement of the locomotive steam 

 engine, and its application to railways have for several years so en- 

 grossed public attention that other means of facilitating the operations 

 of commerce, and expediting the social intercourse of distant masses 

 of people less fascinating perhaps, but not less important, have been 

 comparatively overlooked. The subject of water transport by steam 

 has from this cause received less than its due share of attention. A 

 re-action however appears to have been recently produced, and we 

 have now a swarm of projectors much more largely supplied with zeal 

 ttan knowledge, who not content with advancing in the march of im- 

 provement with that calm deliberation and salutary caution so neces- 

 sary to insure a permanently profitable issue for any great undertaking, 

 would rush to their ends without ever informing themselves of the 

 means at their disposal, and proceed /ler saltum from a channel trip to 

 the circumnavigation of the globe. 



Within the last year, considerable public attention has been directed 

 to the question of the practicability and advantage of establishing a 

 line of steam communication between Great Britain and the United 

 States, and various projects have been started and companies formed 

 for the construction of vessels for that purpose, several of which are 

 already in a state of forwardness. At a meeting of the British Scientific 

 Association held at Bristol last September, one of the topics which 

 engrossed a large share of interest, was the question of the practica- 

 bility of a steam voyage across the Atlantic, raised in the mechanical 

 section. The statement laid before that section by Dr. Lardner ob- 

 tained such publicity at the time through the press, that it would be 

 superfluous to recapitulate its arguments. The conclusions however at 

 which he arrived were briefly these : — That in the present state of the 

 steam engine as applied to nautical purposes he regarded a permanent 

 and profitable communication between Great Britain and New York 

 by steam vessels, making the voyage ix one trip, as in a high degree 

 improbable : that since the length of the voyage exceeds the present 

 limits of steam power, it would be desirable to resolve it into the 

 shortest practicable stages ; and that therefore the most eligible point 

 of departure would be the most western shores of the British [sles, 

 and the first point of arrival the most eastern available parts of the 

 western continent ; and that under such circumstances the length of 

 the trip, though it would come fully up to the present limit of this 

 application of steam power, would not exceed it, and that we might 

 reasonably look for such a degree of improvement in the efficiency of 

 marine engines, as would render such an enterprise permanent and 

 profitable." 



Dr. Lardner then goes on to state that it had been objected to his 

 conclusions, that the data from whence they were derived had been 

 obtained from the performance of steam vessels antecedently to 1S34, 

 whereas since that period considerable improvement was alleged to 

 have been effected in steam machinery, which by diminishing the con- 

 sumption of fuel was considered to have improved the prospects of 

 Atlantic steam voyaging. Of ah the vessels then existing the Medea 

 was universally allowed to be the one which was capable of being im- 

 pelled over the greatest distance with a given quantity of coals per 

 horse power ; she was therefore the most favourable actual standard 

 by which prospects of the Atlantic enterprise could be measured, and 

 was adopted as the basis of the present inquiry. Dr. Lardner then 

 proceeds to show that the same conclusion respecting the Atlantic en- 

 terprise which he had already deduced from the performances of ves- 

 sels antecedently to 1S34, was also deducible from the performances of 

 the Medea, and of other vessels between 1834 and 1S37. 



The misconception which has existed respecting Dr. Lardners 

 opinions upon this question, and which nothing short of raisrepresenta- 

 tion prepense was sufficient to have created, renders it proper here to 

 repeat that the limits which exist to the achievements of steam power 

 are not imposed by any abstract impracticability of performing steam 

 voyages of any length whatever, but by the impracticability of render- 

 ing those voyages sufficiently profitable to confer permanency upon 

 enterprises in steam navigation. The doctrine attributed to Dr. Lard- 

 ner that a steam vessel (or any vessel), if only sea worthy, was incapa- 



ble of proceeding from Great Britain to the coast of North America, 

 is so palpably absurd that it scarcely deserves to be noticed. 



Dr. Lardner has however offered the following observations upon 

 the subject, which we extract from the Monthly Chronicle, Vol. IL, 

 1S3S. 



" A vessel having as her cargo a couple of steam engines and some 

 hundred tons of coal, would be ceteris paribus as capable of crossing 

 the Atlantic as a vessel transporting the same weight of anv other 

 cargo. A steam vessel it is true would labour under some compara- 

 tive disadvantage, owing to the obstruction presented by her paddle 

 wheels, and the paddle boxes which cover them : still, however, it 

 would be preposterous to suppose that these impediments would ren- 

 der impracticable her passage to New York. If therefore such a ves- 

 sel merely transported her machinery and fuel without working the 

 one or consuming the other, she would still make the passage. That 

 a steam ship may be a tolerably good sailing vessel is proved by the 

 fact that the steam frigate Medea, one of the most eflScient steamers 

 in the service of the Admiralty, accompanied the fleet many thousand 

 miles propelled by sails, and without working her engines at ail. If 

 then a steam ship viewed merely as a sailing vessel, freighted with 

 engines and coals, can traverse the Atlantic with certainty, how absurd 

 is it to suppose that the abstract practicability of such a ship making 

 the voyage to New York with the aid of her machinery and fuel can 

 for a moment be doubted ! 



" In fact no doubt has been entertained or expressed as to the prac- 

 ticability of establishing a communication between these countries and 

 New York, by a line of steam vessels. But a difference of opinion 

 has been entertained as to what mode of accomplishing the object may 

 best ensure certainty, safety, regularity Und profit, without which last 

 element it is presumed the other objects could hardly be secured." 



Returning from this digression to the Edinburgh Review, we find 

 Dr. Lardner explaining the inconveniences to which extended steam 

 voyages are subject, arising from the incrustation of salt in the boilers, 

 the deposition of soot in the flues, and other matters of that nature, to 

 which we consider it unnecessary more particularly to refer. He then 

 proceeds — 



"The several circumstances to which we have adverted, constitute 

 difficulties, having the general tendency to abridge the practicable ex- 

 tent of an uninterrupted steam voyage. There remains a still more 

 serious impediment to the extension of steam navigation inherent in 

 the very substance from which the engine at present derives its me- 

 chanical power — an impediment which places a definite and assignable 

 limit, beyond which it is mechanically impossible to extend the voyage 

 of a steamer (of ordinary construction). To form an estimate there- 

 fore of the major limit of the extent of a continuous steam voyage, it 

 will be necessary that we should examine, 1st. The proportion in 

 which the capacity of the vessel may be distributed between the ma- 

 chinery, the fuel, and the objects of commercial transport; and 2ndly. 

 The rate at which the fuel will be consumed in propelling the vessel 

 over a given distance, regard being had to her tonnage and power. 



" Assuming that a certain extent of the capacity of the vessel is 

 appropriated to the mechanical means of propelling her, that portion 

 will obviously be shared between the machinery and the fuel, by which 

 that machinery is moved. 



" The proportion in which this space should be distributed between 

 the machinery and the fuel will vary according to the length of the 

 voyage. As the fuel may be replaced at the end of each trip, and as 

 it is generally advantageous to give the vessel as powerful machinery 

 as the extent of her capacity will admit, it is obviously expedient to 

 reserve as limited a space as possible for the fuel, and to give a pro- 

 portionably increased extent of room to the machineiy. In the shortest 

 class of voyages therefore a smaller supply of fuel being sufficient, a 

 larger space must be appropriated to the machinery, and in proportion 

 as the length of the voyage is increased, the quantity of space neces- 

 sary for the fuel will be augmented, and that allotted to the machinery 

 diminished. To this there must be an evident limit ; inasmuch as the 

 space for the machinery must be sufficiently extensive to contain en- 

 gines of the power necessary to encounter the difficulties of the navi- 



