On Ship-building. 359 



and two'fhirds of this 'product will be the number representing the horse- 

 power. Then will the velocity be equal to twice the cube root of the quotient 

 of the number of horses, divided by the rectangle of the draught of water 

 and the breadth of the vessel. 



His general results are important, and are as follows : — To stem a cur^ 

 rent with the least consumption of fuel, the absolute vehcity of the vessel 

 should be only half the velocity of the steam. That the velocity resulting 

 from the use of the rope and roller is greater than that which results from 

 the use of the paddle-wheel, in the proportion of the cube root of the velocity 

 communicated by the paddles to the vessel: That to enable a vessel to stem 

 a current with an absolute velocity equal to half the velocity of the current, it 

 requires three times the motive power, if that power acts on board the vessel, 

 that would be necessary if the power were applied to the rope : That when 

 the current is rapid, it is advantageous to use the rope for hauling, in order 

 to stem it; but that, if the current is not strong, it is preferable to use the 

 paddles ; and that the paddles should always be used in descending a stream, 

 when the absolute velocity of the vessel is greater than the velocity of the 

 paddles, or when the velocity of the stream is greater than the velocity with 

 which the paddles strike the water, which will generally be the case. 



Much doubtless remains to be done to perfect the theory and practice of 

 steam-boats ; yet in an invention, comparatively so new, it is remarkable 

 how rapid have been the steps already made in their improvement. Ber- 

 nouilli was a man who looked at things largely — one of those chosen mi- 

 nisters of nature, destined in a thousand instances to enlarge her transcen- 

 dant domain ; — yet he thought, only fifty years before the great triumph 

 of steam, that this peculiar application of it was impracticable. How 

 would it delight his ardent and magnificent mind could he now behold 

 its lofty achievements- — its varied and increasing powers — the voyages it 

 has accomplished over the stormy bosom of the Atlantic, and how it has 

 connected the busy stream of the Thames w^ith the mighty waters of the 

 Ganges ? 



Much interesting and important matter now remains to be noticed, not- 

 withstanding the copious length of our analysis, — so wide is the dominion 

 of naval architecture, and so fertile every part of its soil. Let us hope 

 that the spirit which is now awakened respecting it may carry it onwards 

 to the glory and perfection it merits; — that the wooden walls of Old 

 England may obtain whatever advantages the other sciences can impart to 

 it. In the meantime, let the humblest shipwright learn that his country 

 has a claim on the successful application of his powers to perfect the art to 

 which his whole life is to be devoted, and that the noble fabric which his 

 hands has assisted to rear, requires the exercise of his noblest intellectual 

 powers to make it perfect and complete. 



Finally, we conclude with the author of the paper by saying, that it is 

 not in the terrible season of war, when the hopes and energies of man are 

 principally occupied with conquest, that naval architecture can be expect- 

 ed to make its greatest steps towards perfection. In war, as Dupin ob- 

 serves, the object is to do much in a little time, to sacrifice rigorous me- 

 thods to means ready and expeditious, and the way, the best in itself, to 



