184 On the Stability of Vessels. {[Marcu, 
Artic e II. 
On the Stability of Vessels. eae Beaufoy, F.R.S. With Two 
lates. 
(To Dr. Thomson.) 
MY DEAR SIR, Bushey Heath, Dec. 22, 1815. 
Tar part of hydrostatics, which treats on the stability of floating 
bodies, naturally interests the curiosity of most persons in a maritime 
country like Great Britain, and excites ‘the desire of many: to be- 
come acquainted with the law which regulates their equilibrium. 
Being one of those who are attached to this interesting subject, I 
take the liberty of laying before you a series of experiments, which, 
should they prove instrumental in throwing new light on. naval 
architecture, or in improving the construction of vessels, will 
amply recompense the trouble they cost, in the hope that the time 
and expense bestowed on them’ have not been uselessiy employed. . 
jremain, my dear Sir, yours very-sincerely, 
: Marx 'Beauroy, | 
oe Rigg t * a By ayes 
Experiments to verify the Theorems on Stability, particularly M. 
Bouguer’s, with a Description and Drawing of the Apparatus 
with which they were made, and some, Remarks on. the Formation 
of Vessels. i Lol sae 
Tue principal object in making these experiments was to bring 
to the test of experiment the different theorems of various writers 
on naval architecture, particularly those of M. Bouguer for calcu- 
lating the stability of variously shaped floating bodies. ‘This: Gen- 
tleman founds his theory on the supposition that the angles of incli- 
nation assumed by floating bodies are evanescent, which in a. prac- 
tical sense may be regarded as angles which are very small. But as 
vessels at sea frequently, by the pressure of their sails, as well as by 
the action of the waves, make very large angles with the horizon or 
surface of the water, before implicit confidence be placed in any 
theory, it is but prudent fo submit it to the test of experiment. ‘The 
first theorem to be examined is, 
That the stability is in proportion to the squares of the areas of 
the horizontal surfaces or sections. 
2. That the height of the metacentre of the parallelopipedon 
above the centre of gravity of the displaced water is found by 
dividing the square of half the breadth of the parallelopipedon by 
three times the draft of ‘water, that is, the depth to which the 
parallelopipedon is immersed in the fiuid. 
3. That the metacentre of a right angle triangle is elevated as 
much above the line of floatation as the centre of gravity of the 
displaced water is depressed below the surface. 
4. That the metacentre of a semi-ellipsis above its line of floata- 
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