EXPERIMENTS ON THE TIME OF ROLLING. 
627 
22. Experiments made hy Messrs. Fincham and Rawson with the cylindrical model 
(Plate XLVII. fig. 2) to verify the formula 22, which represents the time of the rolling 
of a vessel of that form. 
The following ingenious expedient for determining the time of the oscillations of a 
floating body was suggested by Mr. Fincham and found fully to answer the purpose. 
The motion of the vessel, when floating in the tank, was limited to a rolling motion 
by means of upright guides (A, B, Plate XLIX.), receiving between them the extremi- 
ties of a longitudinal axis fixed in the vessel so as nearly to pass through the centre 
of gravity. A frame, PKL, resting on two parallel rails, was made to traverse uni- 
formly by means of clockwork, M, in the direction of this axis produced, that is, in 
the direction of the length of the model, and at right angles to the direction in which 
it rolled. This frame carried a cylindrical piece of wood, PL, having its axis in the 
direction of the motion of the frame, and its surface so curved that an arm, HI, fixed 
to the model parallel to its length and projecting beyond its extremity, should, as it 
4 l2 
