166 S. Newcomb— Variability of the Earth’s axial rotation. 
a. Eclipse disappearing. 6. Eclipse reappearing. 
C Weight. Cc— Weight. 
1868°65 +33°8 2°0 1868°83 —16°5 6°7 
69°76 +152 12°5 69°45 —23°3 2°0 
70°84 + 8-4 6°3 70°05 —24°2 1°8 
71:90 — 26 9°6 71114 —20°6 8°0 
7250 + 5:3 8°2 72°21 —17°4 21°9 
73°25 +15°0 10-2 73°24 —16°5 26°4 
‘To discuss these corrections by the method of least squares, 
let us adopt the following form for the equations of condition : 
xe +k(t—t,)+m(t—t,)? +C—O=0, 
where ¢ is the year of observation, ¢, =1861-00, x the correction 
of the tables for 1861-00, & and m tle co-efficients to be deter- 
mined from the observations. 
“From these equations we obtain the following normal equa- 
tions : 
a. Eclipse disappearing. 
+ 126°92+ 259°3% + 8227m + 1718=0 
+ 259°3a+ 8227 k ++ 35467m + 1706=0 
+8227 2435467 k +923395m +85480—0 
b. Eclipse reappearing. 
+ 1402+ 455°6h + 12239m— 2111°8=0 
+ 455°62+12239 & + 55150m— 9823 =0 
+1223°92+55150 k& +1558741m—196478 —0 
which give for x, k, and m the values: 
Ecli i i 6. Eclipse reappearing. 
Co=—17°76 3841.25 x,==+12'69 +0°86 
ko=+ 0°08317--0°1553 A,=+ 0°25118+-0°09172 (7) 
Mo=+ 0°06245+-0°02178 m,=+ 0°01753+-0°01356 
probable errors allow it, so that pores we have no right to 
take the mean of the values &, an 
because we do not know the cause of this discordance, and 
cannot therefore make any other combination of the values /, 
with &,, and m, with m,. 
“The combined values of a, & and m are 
@=4+3"52 0-71 
k= + 0°2076--0°0783 
m=-+ 0°3006-+-0°01151 
(8) 
