238 Mr Sharpe, Liquid Motion from a Single Source, etc. 



The shape of the curve is given in Fig. 7. If OY be the perpen- 

 dicular on the asymptote it can be shewn from (65) that OY is 

 about ^th of the radius, so that the boundary strongly resembles 



Fig. 7. 



a cone of semiangle tt/S with source at the vertex. It is interest- 

 ing to notice that if we had such a conical boundary, we might see 

 by only considering the inflow of the liquid at and its outflow 

 at infinity, that equation (63) would hold, and the same would be 

 the case for a boundary having a general likeness to BAD (Fig. 7), 

 but this would give us only the approximate velocity of the liquid 

 at infinity. The above investigation however gives us the whole 

 of the fluid motion from the source outwards. We can also get an 

 infinite number of boundaries having a given reflective power — 

 say for instance defined by equation (63). 



