492 D. P. Todd—The Solar Parallax. 
Tur Equations oF ConpDImTIoN IN 8s. 
Putting, then, 04, 04... . 6A, equal to zero, every photograph 
gives one equation ‘of condition in s of the form 
= a6A + bdD + eda — (0.—C.) 
The normal equations in s are as follow :— 
+ 23°99 6A + 24°71 6D — 28°72 da — 82°17 
+ “oy 710A + 18446 dD — 3°16 da — 439°51 
872dA — 3°16 6D + 48451 da + 21°72 
HU i 
= 
whose solution gives— 
dA = + 1/7181 + 077202 
OD = + 277225 + 07-070 
da = + 070397 + 0/0418 
The probable error of a single photograph is 0°88. 
The sums of the squares of the absolute terms in the equa- 
tions of condition are as follow :— 
nnlw a 627-48 mn}, == 37°02 
i nw == 318°25 nn|y = 115°65 
[nn|p = 130718 nn|o = 414°46 
nn |g = 337°63 
nn |e == 27°83 
nn| = 1433-50 
The sums of the squares of the outstanding residuals are as 
low :— 
vv0|w = 77714 wv |x = 20°44 
VUin = 62°47 Vlg = 59°74 
bet = ae ae VV|o = 95°16 
Wig = 85°67 
v ch — 8°91 
vv| = 358°81 
Tur Equations oF Conpirion IN p. 
Putting, as before, 02,, dA, . . . dA, equal to zero, — photo- 
graph gives one equation of condition in p of the 
0= a@’ dA + W OD + ce do — (0.’—C.’) 
The normal equations in p are as follow :— 
+ po po dA — 1404261 dD — 138999°20 da — 1421094 — 0 
404261 dA + 1521370 dD— 2509311 do + 104421 = 0 
ane 20dA — 25093:110D + 7326-76 da +  2651°6 — 0 
whose solution gives— 
dA = + 177109 + 07109 
dD = + 07-637 + 0°"224 
da = + 07-0252 + 07-0595 
The probable error of a single photograph is 3’°447. 
