170 



PROF. OSBORNE REYNOLDS ON 



and therefore diminishes from infinity as p diminishes 

 from jo, till ^= "527^0, ; then A has a minimum value and 

 increases to infinity as /> diminishes to zero^ as in fig. 2. 



The equations contain the definite law of this variation, 

 which, for a particular fall of pressure, is shown in fig. 2 a. 



For the present argument it is sufficient to notice that 

 A has a mimimum value when p=-^2jpi ', since this fact 



