188 S. Newcomb on the apparent inequalities 
by its agreement with the known difference at particular epochs. 
At the end of the British Nautical mA for 1862 is teas a 
° gen 
both tables agreed with observations, shows that the difference 
of mean motion is certainly affected with no sensible error. 
Burckhardt. Hansen. 
Year. L |) Sec. | Long | Corr. Mean tT Sec. ) Long. Mean | H.-B. 
0 Var. | Period. Longitude. 0 Var. Period.| Longitude. 
Ls aN ie 2 “ 7 itde > Passion ED | Mimosa Gn ee i Pe aX eo eo ee, 
1630/1000 19 28°0/+ 4°9/— 8°0'100 19 24°9/18 14:4) +38°5}—21°4/100 18 31°5)—53~ 
40/347 6 45°4/+ 3°6)/—10°8.347 6 38°2) 5 36°3/4+34°1/—20°0/347 5 50°4/—47- 
50\233 2°7%i\+ 2°5)—12°3|233 53 52°9152 58°3!14 30°0|—17-2/223 53 11°1/—31- 
60/120 41 20°1)}+ 1°6/—12°3/120 41 9:4/40 20-3) + 26-1/—13-1/120 40 33°3|—36° 
70| T 28°37%-4\+ 0-9|—10° 7 28 27-5127 42°21422-51— 81] 7 2% 56°6)—30* 
80|254 15 54°8)+ O-4|— 8°0/254 15 47°2)15 4°2)4+19°2|— 2°3/254 15 21°1/—26° 
90}141 3 12°1)+ O1;)\— 42/141 3 7-8) 2 261/4161/+ 3°9)141 2 46:1)—21° 
1700) 27 50 29°5)+ 0°0/+ 0:2) 27 50 29-7/49 48°1;+13-3/4+10°0] 27 50 11°4;—18°% 
10\274 37 46°8)+ O-1/+ 4°4/274 37 51°3/37 10°0/+10°8!415-6/274 37 36°4,—14' 
20/161 ‘2}+ O-4/+ 8°3)161 25 12°9/24 32°0)4+ 8-5)+20°5/161 25 1°0)—11° 
0} 48 12 21°65) + 0°9/4+11°0| 48 12 33-4!11 59-9 65 4-3 48.12. 24:7) — 8° 
40/294 59 38°9)+ 16, +12°4 294 59 52°9/59 15°91 4+ 4:8) + 264/294 59 47°1)— 5° 
60)181 47 56°2)+ 2°5 +12°2 181 47 10°0/46 37°9}+ 3°3 +26-9/181 47 81|— 2° 
80 68 34 13°6/+ 3°6'4+10°6) 68 34 27-8/33 59°8/+ 2°1/425-7| 68 54 27°6)/— 0° 
70|315 21 30°9)+ 4-9\ 4 78/315 21 43°7/21 21-814 1°2|4+22-9)315 21 45°9)+4 2° 
80|202 8 48°3\+ 6-4/4 3°9)202 586] 8 43°7}4+ 0°5)/4-18°5)202 9 27/+ 4 
88 6} + 8-1|/— 0-4} 88 56 13°4156 571+ 01 +328) 88 56 18°6|4+ 5° 
1800/335 43 23°0'+10°0|— 4°7|335 43 28°4143 27°" 0-0} + 61/335 43 33°8}+ 5-4 f 
10}222 30 40°4/+12-1|\— 8°3|222 30 44:2/30 49°6)/+ O-1;/— 1°1\222 30 48°6|4 4° 
20;109 17 57:8) + 14:4|\—11-0}109 1:2/18 11°6}+ 0°5|— 8-4/109 18 3°7/4+ 2° 
30/356 5 15-2|/+16-9|\—12-4)3 ‘| § 33°5/+ 12|—15-4356 5 19°3|— 0+ 
40/242 52 32°5)+19°6)—12°2/242 52 39-°9/52 55°5'+ 2°1/—21-6/242 52 36°0)— 3°S 
50|129 39 49°9| + 22°5|—10°6)129 40 1°8'40 17°5/4 3° 26°5|129 39 Bi Tt 
60] 16 27  %2)4-26'6)—." 16 27 25°2\27 394)4 4°8|—29-8| 16 27 14-4)—10° 
70|263 14 24°6)+28°9|— 3°8/263 14 49°7/15 1-4/4 6° 31:3/263 14 36°6|—13'1 
Burckhardt’s tables have been selected for this comparison 
because they have been sence compared with observations 
made before 1700. The additions to the Connaissance des Temps 
Vv Burck bards himself giving a com- 
rison of his tables with observations of occultations made by 
ua Hevelius and others, between 1637 and 1700. The 
neral result of this comparison is that the mean longitude of | 
fis tables could hardly have been more than a very few seconds | 
in error in the year 1670. But, the preceding table shows is ea | 
for this epoch Hansen’s mean n longitude is 80” less than Burck- ; 
hardt’s. Therefore, unless we suppose git investi- | 
= 
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a 
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is 
RRO 
WES 
B. 
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23 
ra 
2 
Leer] 
gation to be affected with some ous § e error we 4 
must admit that the mean lo e of ibe 8 tates for the i 
epoch | 1670 i = about 30” too small. 
ependent test of this conclusion I have select- 
ed certain chosen uoed which, with the data available, seemed 
