432 Mr. 8. R. Cook on tJie Distribution of 



millimetre of water pressure. The double circle ap being 

 taken as atmospheric pressure. 



The distribution of the pressure in a vertical plane is given 

 in Table lY . The manometers were arranged to give the 

 differential effect, the excess of the pressure on sphere A 

 over the pressure on sphere B in the line of centres being 

 recorded. The arrangement is shown in Plate XVIII. fig. 6. 



Table IV. 





Difference in pressure 





Difference in pressure 



1 Angle f^. 



in mm. of Avater. ' 



Angle e. 



in mm. of water. 



i 



Pa-Pb. 





Pa-Pb. 







0-30 



190 



0-25 



10 



0-40 



200 



0-20 



20 



0-40 



210 



015 



30 



0-50 



220 



0-05 



40 



0-34 



230 to 310 



000 



50 



0-30 



320 



005 



60 to 120 



0-UO 



330 



015 



130 



0-30 



340 



0-20 



140 



0-34 



350 



0-25 



150 



0-50 



360 



0-30 



160 



0-40 







170 



0-40 







180 



0-30 





1 



8. Tlie Distribution of Pressure for a Perfect Fluid. — The 

 velocity potential for a single sphere moving through a 

 perfect fluid, at rest at infinity, with velocity u is 



<fi = ^u — co^ 9, (15) 



where 6 is measured from the direction of motion of the 

 sphere. The pressure at any point of the sphere is 



f=^«4f-4r, 



where F(^) is a function of the time. 



B^ 'b(^dr -d^dO 



and 



di 



B)' dt + 'ht) dt 





Where tte velocity is constant 



\dej 



=0. 



(16) 



(17) 

 (18) 



(19) 



