316 Oji the Form of the Ark of Noah. 



strongest form of a steam-ship. In this case we should be com- 

 pelled to decline all aid from masts and sails, but the privation 

 would be compensated, by the greater facility with which the 

 ship would make its way against a head wind and sea ; we 

 should want, too, the advantage of a large open deck for those 

 on board ; but this would be compensated by their greater 

 safety in the storm. 



'--Hi having been deemed necessary by the author of the above 

 inquiry, to investigate the stability of equilibrium of a floating 

 body, of the form there assigned to the Ark, he finds the result 

 quite satisfactory. 



The rule, given by Laplace, for determining the stability of 

 equilibrium of a floating body is, " That the equilibrium will be 

 stable in every direction, when the sum of the products of each 

 element of the section of the floating body, at the level of the fluid, 

 into the square of its distance from that horizontal axis, through 

 the centre of gravity of the section, in relation to which the sum of 

 the products is a minimum, — is greater than the product of the vo- 

 ^lume of the displaced fluid, into the height of the centre of gravity 

 of the floating body above the centre of gravity of the volume." 



Supposing now a vessel of the form of the Ark to be im- 

 mersed, by the weight of its materials and lading, to the depth 

 of 6 cubits, which is rather more than one-third of its whole 

 tonnage, and that the weight is so uniformly distributed, that 

 the centre of gravity is the same as if the body were homoge- 

 neous, in that case the former sum would be to the latter in the 

 proportion of 18 to 7 nearly. 



Were the centre of gravity to continue the same, the ratio of 

 the stability woufd decrease with a deeper lading, owing to the 

 rapid decrease of the section of flotation. Were the body im- 

 mersed to the depth of 9 cubits, which is very nearly one-half 

 of its tonnage, the former sum would be to the latter only in the 

 proportion of about 8 to 5, and were it immersed to the depth 

 of 12 cubits, or somewhat less than two-thirds of its tonnage, 

 the ratio of the former and latter sums would be only as 7 to 6. 



But it is quite evident, that, in arranging the lading, the 

 centre of gravity of the floating body may be brought below 

 that of a homogeneous body, and that the facility of doing this 



