THE DISPLACEMENT IN A CASE OF FLUID MOTION. 



at rest, the lines which shew the form taken by a line of particles originally 

 Kt might as it flows past the cylinder. This method, however, does not give 

 the jxnnt where the line crosses the axis of x. I therefore calculated this 

 from the equation 



i i r a 



x = r + yt log 



calculating r for values of x differing by J inch. 



The curves thus drawn appear to be as near the truth as I could get 

 without a much greater amount of labour. 



If a maker of "marbled" paper were to rule the surface of his bath with 

 straight lines of paint at right angles, and then to draw a cylindrical ruler 

 through the bath up to the middle, and apply the painted lines to his paper, 

 he would produce the design of Fig. 1, p. 211. 



