EXPERIMENTS OF MESSRS. FINCHAM AND RAWSON. 
641 
In the triangular model. Experiment 1 , the following dimensions were measured in 
inches : — 
G«=175, G&=l-05, Ha=275 
Ac =2-24, Qw=15-2, Qo =3-9 
elevation of centre of gravity of model, in feet 
175-1 05 
12 
= AH, 
275 — 2’24 
elevation of centre of gravity of displaced fluid, in feet= ^ = AHg 
weight of model in lbs =33*8626 =W. 
.*. by equation 6 , = j X 33*8626 = *5361. 
J5-2 3*9 
Also vertical descent of deflecting weight, in feet=— 77 — ? 
deflecting weight Q in lbs, =*5485 ; 
{ 15-2 3*9'1 
j -3 ^ X *5485 = *5 165. 
The computations on both these models, made in accordance with formula 6 , agree 
with the experiments. 
All the experiments show what we conceive to be important, that the same mo- 
ment of force which is necessary to maintain a .vessel in a position 4 at rest, will 
deflect the vessel through nearly twice 0 when made to act upon a vessel which is not 
deflected. Atwood’s statistical stability therefore appears to us to be of little use, so 
far as the rolling of the vessel is concerned. 
Experiments on the Time of Oscillation. 
To find the moment of inertia of a cylindrical model, whose radius is 13*5 inches, 
weight 197*18 lbs. avoirdupois, round an axis passing through the axis of the 
cylinder. 
ABC is a vertical section of the cylinder passing through 
its centre of gravity G. 
It is required to find the moment of inertia of the cylin- 
drical model, about an axis passing through O, the centre 
of the cylinder at riglit angles to the section ABC, 
For this purpose the model was made to oscillate out of 
the water, upon knife-edges passing thi’ongh O and parallel 
to the sides of the cylinder. Several experiments were carefully made, and the times 
of oscillations were observed through the amplitude of 5°, and 10 °. The appa- 
ratus by means of which the times were obseiwed, enables us to measure the times 
of oscillation to an exactness of *013 of a second, or in round numbers to the one- 
hundredrh part of a second of time, 
4 N 
MDCCCL. 
