EQUATIONS DERIVED FROM THE TRANSIT, 



425 



Taking R = 976"-82, r 31"'42, and mean solar parallax = 

 8"-950 X (l + T^J, we have the equations 



For Internal " Geometrical " Contact 



+ 3"-68 = +o"-ioo4 n -1969 8 R.A. '9772 8 N.P.D. + o"-o3og 8< SR + 8r, 



and for External Contact 



+ 2"- 44 = + o"-og53 '2983 8 R.A. -9463 8 N.P.D. + o"-o376 8< 8R 8r. 

 For Mr. Sidgreaves' observations are obtained the following results : 



Whence the final equations 



For Internal " Geometrical " Contact 

 + 4"'24 = +o"-ioo6 n -ig5g 8 R.A. -9772 8 N.P.D. +o"-o3i7 8 t 8 R + 8 r, 



and for External Contact 



+ 3"-36 = + o"-og54 n -2972 8 R.A. '9467 8 N.P.D. + o"-oZ-j2 8 t 8 R 8 r. 



G. L. T. 



3 i 2 



