314 



Mr /. Brill, Note on the Steady Motion [May 27, 



the equations of motion may be put into the form 



oy ox 



•(1); 



in addition to which we have 



du 9w _^ 



dx dy ' 



dv d'U 



K 



dx dy 

 Equations (1) may be written in the form 



d(j) 



If we write 



^^r(»-.^-^) = o 



.(2). 



{'' - ' -§-) ^2/ - (^ - - -^) d^ = ^ndx, 



and therefore 



u— V 



dx 



9% 

 dy' 



9 log ? 9% 



•(3), 



then equations (2) become 



Eliminating {^ from these we obtain 



.(4). 



8(»*^. %) 



= 0, 



or 



8(«, y) 



2mr=/(x) (5). 



Multiplying the first of equations (4) by dx, and the second by 

 dy, and adding, we have 



