152 Ocean Wave Poicer Ilachinery. 



movement into wliicli the whole oscillation is divided ; and 

 any estimates based on this somewhat tenacious fallacy are 

 of course erroneous. 



The degree of independence or freedom of the mass is 

 jointly proportional to the voluTne and the density, of the 

 elastic medium on which it is poised. Hence, the power 

 will be estimated by assuming perfect independence and 

 multipljang the result by the co-efficient of elasticity. 



By observations made expressly during thi-ee voyages in 

 vessels of 300, 800, and 1,200 tons respectively, it is esti- 

 mated that an ordinary sea-going vessel on a deep-ocean 

 voyage averages six oscillations per minute, with the average 

 angular inclination of 9° thus compounded, viz., 8° 39' on the 

 longitudinal or rolling axis, and 2° 30' on the transverse or 

 pitching axis ; and that the whole movement constantly to be 

 relied on, represents an efficient force of independent inertia, 

 combined upon the three dimensions, equivalent to the whole 

 mass raised at the rate of ] 4 inches per second ; so that if 

 the mass or independent load be represented by M, the 

 working effect will be equivalent to 4 '7 M horse power or 

 upwards of 4| horse power per ton of weight employed.* 



The storm efficiency is of course very much greater ; 

 indeed to those acquainted with the behaviour of ships in 

 heavy seas, little demonstra^tion is necessary to show that in 

 a vessel labouring amongst waves 20 or 30 feet in height, 

 the prodigious force accumulated will exceed practical 

 requirement, and the movements of the load may be reduced 

 almost to zero. 



In a forthcoming analysis of the principle of action, it 

 will be shown that it is precisely the same as if the vessel 

 remained motionless, and the inverted movements of the ship 

 were transferred to the independent load ; the working power 

 consisting of the force requisite to stop such a movement. 



It will thus be seen that as the movement of the ship is 

 the resultant of all the wave forces acting within the total 

 displacement, the entire vessel presents the surface from 

 which the force is gleaned. In other words, she is the 

 receptacle of the moving force of all the particles of water 

 which she displaces ; a power so enormous as to be practically 

 infinite in respect of any tax which can be imposed upon it 

 from within board, so that it may not be too much to assert 



* The computation on which this result is based will hereafter be 

 shown. 



