0 
in the limit, of one of the relative stream lines; so that the 
same particles are always in contact with the cylinder, as 
the ordinary ideal theory requires. 
3.—To trace out the deformation of other lines of 
particles, it is necessary to adjust first the curves in Fig. 2. 
For instance, to obtain curves which have been drawn by 
Maxwell, we arrange the paths in Fig. 3 so that the initial 
points (A) lie in a straight line perpendicular to Oz; then 
by the same process as before, we obtain the successive forms 
of a line of particles which lay in a straight line initially 
| 
FiGurRe 3 
when at a great distance in front of the cylinder. We could 
trace similarly the deformation of groups of particles. 
Fig. 4 was obtained by this method; it illustrates the 
extreme deformation which occurs near the cylinder. Con- 
sider for a moment that the cylinder is at rest and the fluid 
streams past it from left to right. The three enclosed areas, 
equal in magnitude, are successive positions of the same 
group of particles. 
It has been mentioned already that the ordinary solution 
of this problem assumes that the fluid is infinitely divisible 
86 
