D. P. Todd—The Solar Parallax. 493 
The sums of the squares on the absolute terms in the equa- 
tions of condition are as fo 
mn lw = 358'°65 mn} = 38120 
nr|y == 1271749 WN |y — 1924°85 
nn|p = 269°08 nn|, == 2044°68 
NN |g = 1462°97 
NN, == .220°70 
q nn| = 7933°62 
j The sums of the squares of the outstanding residuals are as 
: follow :— 
7 vvlw = 32365 wv]x = 174'34 
‘ vvly = 972°02 VV i_y == 840°69 
4 vl, == 519°77 revo == 1236-90 
2 VO |g = 1232°09 
4 VV |on = 176°04 
‘ fov}] == 5475°50 
Frvat Varuss or 6A, 6D, dz. 
It seems likely that some of the probable errors of these 
quantities which have been derived are illusory. The best 
course, however, which we can now pursue will be to combine 
the values of 3A, 6D, and da obtained from the two solutions 
in ce with the weights depending upon these probable 
err 
ods alee cal, Sea 
We thus have, for dA, 
From solution ins, SA = + 1/"181 + 077202 
From solution inp, JA = + 17109 + 077109 
inal value, dA = + 08075 + 0°:006 
And for 6D, 
From solution ins, JD = + 2/7225 + 07-070 
From solution inp, 06D = + 07637 + 07224 
Final value, 6D = + 2/7083 8 0’7-067 
And for ds, . 
From solution n in 8, da = + 070397 + 077-0418 
From solution in p, da = + 07-0252 + 0” br 
inal value, dao = + 077035 + 0/70 
The assumed value of a being 8’848, we eae finally, for 
the mean equatorial horizontal parallax of the sun, 
8”°883 + 07°034 
corresponding (if we adopt the dimensions of the earth given 
by Colonel A: R. Clarke*) to a distance between the centres of 
the sun and earth equal to 
148,103,000 k:lictabkdre = 92,028,000 miles. 
Washington, April 27, 1881. 
* Geodesy . . . Oxford, Clarendon Press, 1880, page 319. 
