520 
This periodic part is very nearly the same in all Saros-periods. 
It will be given in detail in the second part of this paper. To show 
its general character I give here in Table II the mean for the last 
five periods VIII—XII (1829—1919}, which are the most important 
for the comparison with the observations. The first column contains 
the time ¢ counted in synodie months from the beginning of the 
AA BAE dk 
ETA 
. . | N ~ } + re 
4s |Form.]| t 2s \Form.l t is |Form.]| t hen Form. 
| 
0 0 0/41 —521 - 523 | 88 —573 —546 [129 — 34 — 36 [176 4312 +4 360 
6! — 75! — 84[47 — 560 —572| 94557 —491 [135 + 64 + 45 [182 +311' +356 
12 —143 -. 167[53 —578 — 608 [100 —545 — 426 [141 + 133) +120 [188 +321, +337 
(18 —309 —359 | 59 —654 —631 [106 —362 —354 [141 +237 +203 |194 +305) +306 
24\- 321 —331 | 65 —538 —640|112 --319 —273]153 +239 +247|200 +240! +262 
30 | —441 —406]71 —603 —635}118 —216 —190]159 +262 +295 1206 +272 +206 
36 | —487 —474|77 —582 —616 [124 — 117 —106 [165 +316 +330 [2124174 +140 
| 83 |—577| — 583 171 +314 +352 [218 + 76 + 66 | 
Saros. This periodic perturbation can be represented with unexpected 
accuracy by the formula: 
Noe 
ree ee 
As = — 140—500 sin ey — 16 "26 | EE 
The values computed by this formula are given in the table under 
the heading “Form”. The constant term, of course, is unimportant, 
and could be added to the arbitrary constant of integration AÀ,. It 
would almost entirely disappear, if the Saros was begun at the end 
of the third group, say at about = 121. If the time is expressed 
in years, the formula becomes 
Ig = ~ 140 + 500 sin | 19°.907 (—1900) + 171 | EN Gi 
The course of the perturbation in longitude is remarkably similar 
in the different periods, the irregularities, i.e. the deviations from 
the sine-formula, recurring in each period at the same values of ¢. 
The coefficient of the sine on the other hand varies from one period 
to another. For the first eight periods it oscillates between about 
350 and 400, in the later periods it increases up to about 600 for 
the Saros XII (1901-1919). 
