72 Rutherfurd Photographic Measures of 



The other columns contain the precession constants, whereby 

 the positions of these stars may be reduced to another epoch, T, 

 by the formulae : 



( t — t87^ z 

 *t = a im + A T- 1873 ) + E> ^^-. 



6 T = 6 im + L(T- 1873 ) + M C? ~^ 73)2 - 



