424 



Mr. S. R. Cook on the Distribution of 



Table IV. is a comparison o£ the results of other experi- 

 menters with those given in this paper. 





Table IV. 







Value of Poisson's Ratio. 



Material. 







Bauschinger. 



Strom ever. 



From Table 11. 



Mild Steel .. 



•29 



•273 lo' 

 •300 



•271 to 

 •281 





Wrought Iron ... 



•26 to 



•279 to 



•270 to 





•31 



•301 



•289 



Brass Rod 





•283 to 

 •357 



•320 to 

 •351 







Copper Eod 



Cast Iron 





•325 



•310 to 



•16to^l9 



•148 to 



•340 



•228 to 





(Tension) 



•269 



•270 





•32 to -38 









(Compression) 







In conclusion I must acknowledge my indebtedness to my 

 colleague, Mr. E. L. Watkin^ M.A., for his valuable assistance 

 in carrying out these experiments, w^hich w^ere made in the 

 Engineering Laboratory at Universit}^ College, Bristol. 



LVI. On the Distribution of Pressure around Spheres in a 

 Viscous Fluid. Dy S. E.. Cook, J/.aS., -4.il/.. Former 

 Felloio in Physics in the University of Nebraska, Instructor 

 in Physics, Case School of Applied Science^. 



[Plate XVin.] 



1. rpHE motion of a sphere in an incompressible friction- 

 J_ less fluid, at rest at infinity, has been discussed by 

 Poisson, Stokes, Rayleigh, Kelvin, Koenig, and others. The 

 solution in its present form was first given by Stokes in his 

 celebrated paper '* On Some Cases of Fluid Motion,'''' read 

 before the Cambridge Philosophical Society in 1843 f- 



On the principle that the mutual force acting between two 

 adjacent elements of a fluid is normal to the surface which 

 separates them, Stokes finds that the kinetic enero^y T of a 

 sphere moving in an incompressible frictionless fluid at rest 



* Communicated by Prof. D. B. Brace : read before the American 

 Association for the Advancement of Sciences at Washington, January 1, 

 1903. 



t Camb. Trans, vol. viii. p. 184 ; Math. Papers, vol. i. p. 41. 



