42 Experiments mads at Greenland Dock. [Jan. 



find these plates in equilibrio, and consequently no effect could be 

 produced upon any substance interposed between them. 



(To be continued.) 



Article IV. 



Some Account of a Set of Experiments made at Greenland Dock, 

 in the Years 1793, 1794, 1795, 1796, 1797, and 17!)S. By 

 Col. Mark Beaufoy .; Capt. James Scott, of the First Regiment 

 of Royal Tower Hamlets Militia ; and Capt. John Leard, Com-' 

 manding Earl Stanhope's vessel Ambo. 



These experiments were at first conducted under the direction, 

 and at the expense, of the Society for Improving Naval Architec-* 

 ture • and after the dissolution of that society, they were continued 

 at the expense, we believe, of Col. Beaufoy. The object in view 

 was to determine experimentally what particular forms of bodies 

 move through the water with the least resistance, both at the sur- 

 face and when immersed to a certain depth under the surface. It 

 is well known that the theoretical investigations of this important 

 subject have led to very little of practical value: so that ship 

 building is still, in a great measure, an empyrical art; and no 

 person can pretend to foretell, with certainty, whether a new built 

 ship will sail ill or well. Hence experimental results are the only 

 ones to be depended on in practice. The experiments in question 

 having been made with great care and perseverance, and having 

 been very much varied, as far as relates to the form of the moving 

 body, and to the velocity of its motion, cannot fail to prove ac- 

 ceptable to practical men ; and, if properly attended to, might 

 introduce some very important alterations and improvements in the 

 forms of our ships, and the method of building them. 



These experiments are so numerous, that it would be impossible 

 to introduce them all into a work of this sort without devoting to 

 them the whole of several successive volumes, a sacrifice which we 

 could not make consistently with propriety. All that w-e shall 

 attempt, therefore, at present, will be to exhibit a view of the 

 weight necessary to move each of the substances tried with one 

 determinate velocity : though, perhaps, hereafter we may be 

 tempted to exhibit a more complete detail of the experiments 

 respecting such of the forms as seem to move with the greatest or 

 with the least resistance. 



The apparatus was very simple and well conceived. The cord 

 fixed to the body to be moved in the water passed under a light 

 wheel, and from that to the top of a three-legged stand, where it 

 was attached to a system of pullics, to which a box was hung to 



