552 
COLONEL SABINE ON THE INFLUENCE OF THE MOON ON THE 
Table I. 
Lunar hours. 
Deflections. 
Lunar hours. 
Deflections. 
Lunar hours. 
Deflections, l, Lunar hours. 
Deflections. 
21 
22 
23 
0 
1 
2 
3 
Scale divisions. 
— 0-15 
- 0-35 
‘— 0-30 
- 0*35 
— 0-32 
— 0-225 
— 0-14 
4 
5 
6 
7 
8 
Scale divisions. 
+ 0-14 
+ 0-175 
+ 0-17 
+ 0-11 
+ 0-01 
9 
10 
11 
12 
13 
14 
15 
Scale divisions. | 
— 0-12 16 
— 0-30 ' 17 
— 0-43 i 18 
— 0-42 i 19 
- 0-30 20 
- 0-19 ; 
— 0-12 ! 
Scale divisions. 
+ 0-03 
+ 0-17 
+ 0-31 
+ 0-11 
+ 0-06 
1 
We may represent these numbers by the general formula 
A,= -0-10]25+ 0147sin(a+36° 43')“-2993 sin (2a + 276° 51') 
_-0045 sin (3a+247° 23') +'0234 sin (4a+ 68° 13') 
+ •0376 sin (6a+ 49° 19') — *0195 sin (6a+16°08') 
-•0135 sin (7a+345° 25') — -0109 sin (8a + 6° 35') 
— •0266 sin (9a+307° 22') + -0244 sin (10a+58° 17') 
+•0043 sin (ll« + 87° 0l') + -00833 cos 12fl ; 
a being the difference between x and 18 lunar hours expressed in hours and parts of 
an hour multiplied by 15°. • , j 
With this formula we obtain the times of greatest easterly deflection 0 22 an 
llh 23“ and the amounts 15"-7 and 19"-1 : and of greatest westerly deflection 5'' 0“ 
and 18”’ 0“ and the amounts 7"'6 and 13"-4. If we suppose the differences between 
the times and amounts of the two extreme easterly deflections to be due, wholly or 
in part, to accidental irregularities in the amount of the deflections at the different 
hours, the exact values of which would probably require a longer period of observa- 
tion to determine, -and if the same remark be also applicable to the times and 
amounts of the two extreme westerly deflections, -we find, as the mean of the times of 
extreme easterly deflection, 11” 53“-5, and 23” 53“-5, and the amount 17 '4 ; and o 
the extreme westerly deflections 5” 30“, and U'* 30“, and the amount^O ‘5 ^ making 
the total amount of the variation due to lunar influence (17"'4+10 5— )27 9. 
The progression being a double one in the 24 lunar hours the variation passes four 
times through zero when the lunar variation disappears or equals 0. These times as 
given by the formula are 3” 29“ ; 8” 08“ ; 15” 45“ ; and 20” 27“ ; or 3” 33“ belore, 
and 3” 29“ after the moon’s upper culmination ; and 3” 52“ before, and 3 45 a ter 
the moon’s lower culmination. 
It is quite possible that when the facts shall have been more precisely determined, 
it may prove that neither the times nor the amounts of the tvvo easterly deflections 
are strictly symmetrical ; and so also in regard to the two extreme westerly deflections. 
With a full consideration of what may be due to accidental irregularities, an par- 
ticularly to the influence on the precise time of the extreme elongation of even a vei\ 
small error occurring near the turning hours, there still seems an indication ot 
systematic difference, which is the more deserving of attention, because M. Kreil 
