INTRODUCTION. 



49 



The curve of resistance derived from these examples instead of being a pa- 

 rabola, will be of the following species. Fig. 1 and 2. 



Y A 



AX and AY rectangular co-ordinates. 

 Velocity measured on AY, and resistance on AX. 

 AP the parabola resulting from the squares of the velocities. 

 AMm R the line of resistance, M the point of first maximum, and m the 

 succeeding point of minimum. 



The causes of these deviations from the law of the squares of the velocities, 

 are fully investigated in the course of observations forming Part I. of this paper, 

 Part II. being fiUed with the details of the experiments of 1834, and Part III, 

 with those of 1835. 



The first element of deviation which presented itself, was a phenomenon of 

 Emersion of the solid from the fluid, due to the velocity of the motion, and by 

 which the djTiamical immersion of the floating body is rendered less than its sta- 

 tical immersion in the fluid. The law connecting this emersion with the velocity 

 of the solid is deduced in Sect. (1.) from elementary considerations, and coincides 

 with the experiments. 



Having determined the effect of motion upon the floating body itself in rela- 

 tion to the fluid, I have next examined the effect produced on the particles of the 



VOL. XIV. PART I. G 



