166 Analijsis of Scientific Books and Memoirs. 



appears ; and we are persuaded that the welfare of tlie country will be es- 

 sentially promoted by fostering native talent. 



We particularly admire the clear and methodical method adopted in the 

 article, of applying the method of equidistant ordinates to the computation of 

 the displacement and other kindred inquiries. The tabulating the different 

 systems of ordinaies, and expressing the solidities of the sections in intelli- 

 gible mathematical forms, makes the long train of calculation both easy 

 and convenient. In investigating the general question of stability, the au- 

 thor has properly adopted the rigorous method of Atwood, and, after inves- 

 tigating its theoretical conditions, follows that profound mathematician in 

 applying its principles to bodies of diflPerent forms, finding the centres of 

 gravity of their entire volumes, and of the volumes immersed ; calculating 

 the area of the section of the displaced volume, and the length of the line 

 representing the measure of the body's stability; and finally, computing the 

 equivalent effect of the wind acting on the sails at some given distance from 

 the axis of the body. And, lest there should be any of the readers of the 

 Encydopwdia not versed in the flowery and delicate calculus of the sines, 

 or capable of applying the immortal discovery of Napier, he has added the 

 excellent experimental illustrations of Beaufoy, all of which tend to confirm, 

 as they ought, the former results. 



The method of Atwood for computing the stability is rigorous and ex- 

 act, but excessively laborious ; and therefore the author properly remarks, 

 that, in cases where a great accuracy is not required, the metacentric raetliod 

 of Bouguer may with propriety be adopted. In applying the two methods 

 to a seventy-four gun ship, the author found the following results. 

 By the method of Atwood the stability at an angle of ten de- Tons. 



grees is represented by 2115.9, 



and by the method of Bouguer 2135.4, 



the metacentric stability diflPering from the true stability only 19.5 tons, 

 or about l-108th of the whole quantity. 



There are some chances of error, however, in the application of the meta- 

 centric mode, which the author has properly referred to, and we join with 

 him in cordially recommending the method of Atwood, notwithstanding 

 its long calculations. 



In investigating the position of the centre of gravity, he illustrates it by 

 theoretical considerations, by actual computation, and how the same may 

 be performed experimentally. He gives a neat practical rule, which we 

 transcribe. ** Divide the difference of the momenta of the inclining forces 

 by the difference of the same forces, and the result will be the distance of the 

 centre of gravity of the ship, from the centre of gravity of the displacement." 



We regret that our limits will not permit us to follow him through his 

 investigation of the effect of the total force acting at the centre of gravity, 

 on the pitching and rolling of a ship, — two considerations of great import- 

 ance in the structure of a vessel. Nothing, as Chapman observes, is more 

 difficult than to construct a ship, so as to unite the qualities of sufficient 

 stability and easiness of rolling, anJ thj difficulty is very much increased 

 in the construction of merchantmen. 



On the mysterious and difficult subject of the resistance of fluids, the 



