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of floating Bodies , and the Stability of Ships. 127 
the works of M. Euler and Bouguer, is of great importance 
to the advancement of this science : for by such investigation, 
so far as the data are sufficient, the qualities of vessels are 
traced to their true causes, and are explained by general laws ; 
whereas the principles derived from mere observation are 
scarcely ever applicable beyond the cases in which they have 
been experienced in practice. 
Whatever may have been the means by which naval ar- 
chitecture receives progressive improvement, _ it seems to be 
generally allowed, that the art of constructing vessels has, at 
the present period, attained to a degree of perfection far sur- 
passing any that has been known to former times, either an- 
cient or modern ; yet it is equally certain, that some prin- 
ciples, by which the construction of vessels is materially in- 
fluenced, still remain to be developed and explained. It is 
frequently remarked by navigators, as well as by naval archi- 
tects, that alterations apparently the most trivial, in the form 
of a vessel, in the distribution of the ballast, or in the position 
and extent of the masts and sails, will wholly change the qua- 
lities of a ship from bad to good, or the reverse. As these 
changes cannot be attributed to fortuitous causes, it is neces- 
sary to allow that they are consequences of principles cer- 
tain and definite, though in many cases unknown, or im- 
perfectly estimated by conjecture. The proportions and dis- 
position of parts, which operate to produce good or bad ef- 
fects on the sailing of ships, are probably in these instances so 
intricately combined as to make it scarcely possible from mere 
observation, however extended and diversified, to account sa- 
tisfactorily for changes so remarkable : it must also be ac- 
knowledged, that some of the data on which the theory of 
naval architecture is founded, being imperfectly known, parti- 
