TRANSACTIONS OF THE SECTIONS. 431 



largest of which, it is believed, have never exceeded 14 feet in 

 length. They were generally much smaller. The results which 

 have been thus obtained on small bodies have not been found 

 to agree with results similarly obtained on larger bodies ; and 

 not only has this been the case, but experiments conducted ap- 

 parently with equal care by different individuals have even led 

 to different results. 



Naval architecture has, consequently, gained but little from 

 the labour that has been bestowed upon these experiments, 

 and the forms which have been given by different individuals 

 to ships have depended rather upon the fancy and general ex- 

 perience of those individuals than upon any facts which this 

 branch of experimental science has furnished. 



In order to discover that form of the body of a ship which 

 shall oppose the least resistance to its passage through the 

 water, the author recommends that experiments be made on 

 ships themselves, under all the ordinary circumstances of 

 sailing. 



These experiments must be conducted, not in the mode in 

 which experimental squadrons have hitherto been, viz. by 

 comparing together the sailing qualities of ships that have va- 

 ried in every particular. We are no more justified in saying 

 that results obtained in this way have proved which form of 

 body is best calculated for velocity, than we are in saying which 

 ship has been the best managed. 



If it be desirable to discover by experiment which of two or 

 more forms is best adapted for velocity, it is, of course, neces- 

 sary that the form shall be the only variable element ; the ships 

 in every other respect must be exactly similar. 



By the aid which the mathematics afford, we shall be able 

 most completely to accomplish this. Let a ship be given which 

 sails well, and which is in all other respects an efficient man-of- 

 war as regards capacity, stability, &c. &c. Let this ship be 

 docked, and let the most complete drawings of her form be 

 made, from which we shall be able to calculate exactly every 

 necessary element, such as displacement, area of midship sec- 

 tion, of load water section, stability, &c. ; and let the surface 

 of sail, the position and rake of masts be also acertained. 



Then let one or more ships be constructed, having exactly 

 the same principal elements as the given one, with whatever 

 difference of form it may be thought proper to select, and let 

 the same surface of sail be given to them all. We shall thus 

 have the same weights to be moved, and the same propelling 

 force to move them ; the result will, of course, show which form 

 is best calculated for velocity. 



