sos Mr. Atwood's Disquisition on 
times, be desirous of discovering in what particular circum- 
stances of construction this property consists, and according to 
what laws the stability is affected by any varieties that may 
be given to their forms, dimensions, and disposition of con- 
tents ; which are determined partly according to the skill and 
judgment of the constructor, and partly by adjustments after 
the vessel has been set afloat. 
Little more than a century has now elapsed, since the theory of 
mechanics was first applied to the construction and management 
of vessels ; whatever principles had been previously adopted, for 
regulating their forms and equipment, as well as for directing 
them in the ocean, were the result of experience and observation 
alone : a mode of arriving at truth, however advantageous in 
many respects, yet not entirely to be relied on in this instance, 
for explaining satisfactorily, and reducing to system, pheno- 
mena depending on the intricate combination of causes which 
influence a vessel's motion, and equilibrium, at sea. The theory 
of mechanics is known to explain all effects that can arise from 
the action of forces, however complicated, of which the quan- 
tities and directions are defined with sufficient precision. This 
science, having been greatly extended, and successfully em- 
ployed, by Sir Isaac Newton, in the investigation of causes 
requiring the most profound research, would naturally be re- 
sorted to, for a solution of many difficulties that occur in the 
theory of naval architecture, which could not be obtained from 
any other mode of considering this subject. The practice of 
ship building having been many ages antecedent to the dis- 
covery of the theory of mechanics, one object of theoretic 
inquiry must necessarily be, to explain the principles of con- 
struction and management which experience and practical 
