PHILOSOPHICAL 
TRANSACTIONS. 
X. A Disquisition on the Stability of Ships . By George 
Atwood, Esq . R R. S . 
Read March 8, 1798* 
The stability of vessels, by which they are enabled to carry 
a sufficient quantity of sail, without danger or inconvenience, 
is reckoned amongst their most essential properties ; although 
the wind may, in one sense, be said to constitute the power 
by which ships are moved forward in the sea, yet, if it acts on 
a vessel deficient in stability, the effect will be to incline the 
ship from the upright, rather than to propel it forward : sta- 
bility is therefore not less necessary than the impulses of the 
wind are, to the progressive motion of vessels. This power has 
also considerable influence in regulating the alternate oscil- 
lations of a ship in rolling and pitching; which will be smooth 
and equable, or sudden and irregular, in a great measure, ac- 
cording as the stability is greater or less at the several angles 
of inclination from the upright. From constantly observing 
that the performance of vessels at sea depends materially on 
their stability, both navigators and naval architects must, at all 
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