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 
— ^5 — - 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 18 to July 19. 
b. in. 5. 
19th P' = l8 19 41 -83 
18th P =18 32 21-88 
h. ra. 9. 
L' = 10 29 33*97 
L = 10 46 13-60 
P' — P = 23 47 i9'9S L> — L = 2 3 43 2 0'37 
(P'-P)-(L'— L) = 3 m 59 »-s8 
- f»‘ x »'•?? = r = 4- 
23“ 43" 2o’"37 
From July 19 to July 20. 
20th 
20th P' 
19th P 
h. m. 9. 
17 43 3i’3° 
18 3 32-55 
18 23 35-60 
18 43 42-15 
Mean 
= 18 13 35-40 
= 18 19 41-83 
h. in. s. 
9 49 29-60 
IO 9 27-80 
IO 29 27-20 
IO 49 30-85 
Mean 
L' ;= 10 19 28-86 
L ss 10 29 33-97 
P' — P = 23 53 53-57 L'-L = 23 49 54-89 
(P'_ P) — (L'— L) = 3“ 5 8*-68 
3- x 3 -;8--68 _ „ 6 _ 
*l h 49 m 54*' 89 * 3 
From July 20 to July *1. 
h. m. 9. 
2 1 St P' = l8 14 15-18 
20th P = 18 13 35-40 
It. m. 3. 
L ‘ zz 10 16 14-18 
L = 10 19 28 86 
P' *— P = 24 o 39-78 L' - L = 23 56 42-62 
(P' — P) — (L' — L) = 3 m 57 *-i6 
24" X 3 
23b 5 6 m 42’-62 
576-16 
= r = 
3“ 57*‘7°- 
From July 21 to July 22. 
h. in. «. h. m. a. 
22d P' ZZ 18 II 24-77 L' == 10 9 24-63 
2 1st P = 18 14 15-18 L = 10 16 1 1 -48 
P'^-P= 23 57 9-59 L'-L = 23 53 13-15 
(P — P) — (L' — L) =3- 56*- 44 
24 h x 3 m 5 6a, 44 
23“ 53 m *3 s '*S 
= r = 3“ 5 7 * ' 5 6 
MDCCCXXVII. 
Pp 
