304 SIR F. W. DYSON, PROF. A. S. EDDINGTON AND MR. C. DAVIDSON ON A 

 19. The values of Dx and Dy were equated to expressions of the form 



ax + by + c + aE I (= Dx) 

 and 



where x, y are the co-ordinates of the stars given in Table I., and E.,, E y are coefficients 

 of the gravitational displacement. 



The quantities c and / are corrections to zero, depending on the setting of the scale 

 plate on the plate measured, a and e are differences of scale value, while b and d depend 

 mainly on the orientation of the two plates. The quantity a denotes the deflection at 

 unit distance (i.e., 50' from the sun's centre), so that aE x and aE y are the deflection in 

 R.A. and Decl. respectively of a star whose co-ordinates are x and y. 



The left-hand sides of the equation for the seven stars shown are : 



20. Normal equations formed from these equations of condition are as follows : 



TABLE III. Eclipse Plates Right Ascension. 



-OOOc +1-6576 +l-787a +0-226* 

 +4-664 +2-089 +0-335 

 + 4-094 +2-534 

 +3-142 



+4-2716 +l-666a +0-281a 

 +3-683 +2-476 

 +3-135 



+2-988a +2-366a 

 +3-116 



I. 



+ 2-159 



-0-063 +0-986 +1-320 +0-866 +1 



II. III. IV. V. 



+2-986 +3-250 +2-461 +2-185 



051 



VII. VIII. 



+3-263 +2-648 

 + 1-464 +1-130 



= +1-034 +1-689 +1-866 +1-469 +1-480 +1-972 +1-723 



= +0-712 +0-919 +0-924 +0-860 +0-844 +0-930 +0-973 



= -0-575 +0-278 +0-550 +0-283 +0-533 +0-691 +0-502 



= +0-483 +0-928 +1-037 +0-841 +0-923 +1-140 +1-048 



= +0-643 +0-823 +0-820 +0-781 +0-774 +0-826 +0-888 



= +0-707 +0-820 +0-822 +0-731 +0-715 +0-871 +0-852 



= +0-681 +0-805 +0-784 +0-762 +0-739 +0-780 +0-855 



+l-242a = +0-121 +0-156 +0-133 +0-183 +0-173 +0-090 +0-180 



a = +0-098 +0-126 + -107 +0-148 +0-140 +0-073 +0-145 



a = +0-158 +0-174 +0-189 +0-127 +0-128 +0-233 +0-169 



b = -0-203 -0-011 +0-048 +0-007 +0-042 +0-066 +0-042 



