318 SIR F. W. DYSON, PROF. A. S. EDDINGTON AND MR, C. DAVIDSON ON A 
Table XL—Check Plates, Measures. 
Approx. Co-ords. 
7r 
— ftj. 
-h- 
^2- 
-G- 
G- 
-J,. 
G- 
-G- 
Star. 
X. 
y- 
Ax. 
Ay- 
Ax. 
Ay. 
Ax. 
Ay- 
Ax. 
Ay- 
Ax. 
Ay- 
1 
1-41 
20-31 
4346 
7180 
3199 
4259 
6012 
7375 
3921 
8796 
5435 
4399 
2 
5-89 
12-74 
3865 
6405 
3394 
4129 
4922 
6132 
3039 
7440 
5978 
4170 
4 
9-46 
11-13 
3640 
5932 
3408 
4118 
4369 
5366 
2638 
6776 
5966 
4441 
.5 
12-00 
6-84 
3311 
5590 
— 
3831 
4752 
1938 
6156 
— 
4314 
6 
12-80 
27-33 
5415 
6561 
3192 
5140 
7689- 
5925 
5379 
7580 
5032 
5794 
7 
13-75 
13-78 
4076 
5630 
3496 
4290 
4891 
4805 
3101 
6461 
5906 
4826 
8 
15-50 
24-38 
5125 
6300 
— 
— 
— 
--- 
— 
— 
5139 
5412 
10 
20-13 
10-49 
3965 
4940 
3679 
4505 
4656 
3568 
2866 
5370 
6398 
5229 
11 
20-81 
0-93 
2874 
4352 
3876 
3759 
2845 
2815 
1238 
4758 
7268 
4482 
12 
22-91 
6-23 
3685 
4436 
3931 
4158 
4039 
2738 
2270 
4551 
6765 
5076 
13 
26-46 
8-96 
4222 
4288 
4045 
4326 
4724 
2232 
2720 
4120 
6836 
5561 
The unit for x and ^ is 5 millimetres, which is approximately equal to 5'. The 
differences Ax, Ay are given in units of the fifth place of decimals = 0"-003. The 
centre of the plate is near a’ = 14, ^ = 14. 
Plate-constants were then calcidated in the usual way, by the formula) 
Ax — ax ^ hy c 
Ay = dx A- ey -{- f 
• These were applied, and the residuals A^x, A-yj converted into arc are as follows :— 
Table XII. — Check Plates, Residuals. 
-«i- 
-d,. 
Mean. 
Star. 
A^x. 
Ayj- 
A^x. 
Ayy- 
AjX. 
Ayj- 
Aye. 
Ayy- 
A^x. 
Ayy- 
AjX. 
Ayy- 
1 
ff 
-0-02 
n 
-0-02 
II 
+0-29 
n 
-0-34 
u 
+0-02 
u 
-0-07 
n 
-0-03 
n 
+0-22 
n 
+0-49 
n 
+0-01 
n 
+0-15 
n 
-0-04 
2 
+0-39 
+0-15 
+0-16 
+0-14 
+0-69 
0-00 
+0-69 
-0-29 
+0-10 
-0-23 
+0-41 
-0-05 
4 
-0-14 
-0-04 
-0-16 
+0-09 
-0-38 
-0-12 
-0-02 
-0-37 
-0-54 
+0-12 
-0-25 
-0-06 
5 
-0-08 
+0-35 
— 
— 
+0-25 
+0-19 
-0-21 
-0-21 
— 
-0-01 
-0-01 
+0-08 
6 
-0-06 
-0-10 
-0-28 
+0-27 
-0-09 
+0-14 
-0-10 
+0-12 
+0-15 
+0-49 
-0-08 
+0-18 
7 
-0-06 
-0-28 
-0-10 
-0-16 
-0-74 
-0-09 
-0-31 
+0-02 
-0-39 
-0-12 
-0-32 
-0-13 
8 
-0-30 
+0-34 
— 
— 
— 
— 
— 
-0-38 
-0-68 
-0-34 
-0-17 
10 
-0-02 
-0-10 
-0-21 
+0-52 
-0-15 
+0-16 
+0-08 
+0-25 
-0-08 
+0-34 
-0-08 
+0-23 
11 
-0-46 
-0-01 
-0-13 
-0-22 
-0-13 
+0-11 
-0-13 
+0-71 
+0-30 
-0-28 
-0-11 
+0-06 
12 
+0-16 
-0-14 
+0-13 
-0-04 
+0-19 
-0-06 
+0-17 
-0-09 
-0-13 
+0-08 
+0-10 
-0-05 
13 
+0-59 
-0-12 
+0-32 
-0-26 
+0-34 
-0-25 
-0-13 
-0-38 
+0-48 
+0-28 
+0-32 
-0-15 
The mean residual without regard to sign is ± 0"-21, from which the probable error 
of a determination of Ax oi Ay is ±0"'22. 
