of the Royal Observatories of Greenwich and Paris. 289 
equation to be added to 24 hours of chronometer time, to 
obtain the corresponding interval of sidereal time; and 
■■ ^ —- is the equation to be added to any portion of chro¬ 
nometer time (F' — F), to reduce it to sidereal time. 
Computation of the rates of the Chronometers. 
1. Lignieres Chronometer. 
From July i8 to July 19. 
h. ra. i. 
19th P' = 18 19 4I‘83 
i8th P = 18 32 21-88 
h. m. s. 
L' = 10 29 33*97 
L = 10 46 13*60 
P' — P = 23 47 19*95 L'—L =r 23 43 20*37 
(P'_P)_- (L' —L) = 3” 59’*s8 
^4“ X 3” 59’-58 = r = 4” 2»*38. 
23'* 43™ 2o“*37 , 
From July 19 to July 20. 
20th 
h. tn. s. 
17 43 3»’30 
18 3 32*55 
18 23 35*60 
18 43 42-15 
Mean 
h. lu. s. 
9 49 29*60 
10 9 27*80 
10 29 27*20 
10 49 30*85' 
Mean 
20th P' 
19th P 
= 18 13 35*40 L';= lo 19 28*86 
= i8 19 41*83 L =: 10 29 33*97 
P' — P = 23 53 53*57 L-L = 23 49 54*89 
(P'_ P) — (L'— L) = 3” s8'*68 
= ,=4-0-36. 
*3' 49* S4-'89 
From July to to July *t. 
h. m. a. h. m. 3 , 
2istP' = i3 14 15*18 L' = 10 16 14-18 
20th P = 18 13 35*40 L = 10 19 28 86 
P' — P =: 24 o 39*78 L' - L =2 23 56 42-62 
(P'P) _ (L'_ L) = 3'"S7'*«6 
24** X 3 ™ 57®-i6 „ , 
-W^-4^6^ = ^ = 5 “ 57-70. 
From July 21 to July 22. 
h. ra. s. Ii. ra. g. 
22d P' = 18 II 24-77 L'= 10 9 24-63 
'‘2istP 2= 18 14 15*18 L = 10 16 ri''48 
P'—P=-23 57 9*59 L'-L = 23 53 13-15 
- (P'—P) —(L'-L) =3-56‘-44 
_24» X. 3 l5 6 >4. = r = 3“ 57-56. 
23** 53“‘3“'»S 
MDCCCXXVII. 
Pp 
