276 S&S. Newcomb and E. S. Holden on the Periodic Changes, ete. 
which was done by the application of corrections derived from 
the following formule :— 
For Horizontal Diameter. : 
Greenwich 1862-70: —0*-023 cos 0—0**006 sin 6—0*-016 cos 20 
~+0*011 sin 2 6, 
Washington 1862-65: +-0°-008 cos 9—0*-010 sin 0, 
xi 1866-70 : +-0°-001 cos 6—0°-019 sin 4. 
For Vertical Diameter. 
Greenwich 1862-70: —0':47 cos 6—0'"13 sin 6—0'°07 cos 26— 
0’°12 sin 2 6, 
Washington 1862-65: +0'°09 cos 6+40'"21 sin 4, 
. 1865-70: —0'09 cos 6-+-0'"02 sin 4. 
Kach residual error of ephemeris diameter (diminished by the 
corresponding personal error) was now further corrected by the 
application of a correction derived from the above formule, and 
a series of residuals formed. Whenever a Washington and a 
Greenwich observation were made on the same day, the corre- 
sponding corrected residuals were multiplied together, and the 
sums of these products were tabulated as below. 
| Sums or Propvots. N Vaca gh meen 
Year. Hor. Diam. | Vert. Diam. Hor. Diam. | Vert. Diam. 
1862 —0°0492 — 19°69 33 24 
+0°0007 — 2°10 40 25 
64 —0°0185 — 12°55 44 24 
65 +0:0094 + 13°87 49 41 
66 | +0°0151 | + 7-20 48 54 
67 —0°0364 — 841 31 28 
68 | +0°0122 | + 267 37 39 
6 — 0433 + 6°73 6 it 
1870 — 0°0843 — 10°86 25 25 
= | —0%1077 | —23/-14 313 271 
We see by this table that there is a decided preponderance of 
negative products. This result seems conclusive against the 
to 
—— at Greenwich corresponded to the smaller ones at 
from a tendency to vibrations of short period, probably not 
differing much from 10 hours. We are, however, inclined to 
attribute this result to chance. The mean value of the prod 
Ceo ah eee 
