( 89 ) 
ie 1879 | 1887 
79—82 | 88—86 | 87—91 | 92—96 B 
| 1886 | 1896 
May... .)s. 4-37 | +38) + 22 | + 40}, +38] + 31 
JUNE. |. Ks. +414; +24) +23; +27] +19) +2 
July.... .| 4-12) +22) +13) — 4] +17} + 5 
August.... — 3| + 7] — 4] — 16] + 2! — 10 
September.) — 38} — 32} — 27} — 9] — 35] — 18 
October...) — 64 | — 85 | — 29 | — 23] — 74 | — 26 
November. — 22 | — 54 | — 26| — 21] — 38| — U 
December. — 22 | — | —13| —16}] — 24| — 14 
January..| +12} — 5| — 7| — 6] + 4] — 6 
February.| — 1; +19; +41) — 9] + 9; + 1 
March....| + 40} +34} +1411} — 8] +37; + 1 
April sa +39; +46) +30; +24) +2) +97 
During the period 1887—1896 the periodicity can be very satis- 
factorily represented by a simple sinusoide. We find: 
T— May 5 
3650 
where the amplitude has been expressed in tenthousandth parts of a 
second *). 
For the first period such a representation is impossible, and even 
when a term containing the double angle is introduced, the repre- 
sentation is not entirely sufficient. In that case we find: 
T— Apr. 24 T— Apr. 23 
Ar = + 455 cos 22 —_——— — 95 cos 42% ——______. 
360 365 
An entirely satisfactory representation can only be obtained by an 
empirical curve. 
This curve, together with the points which indicate the observations 
to be represented, is here reproduced in fig. 1. The sinusoide of the 
second period is given in fig. 2”). 
Moreover the following table gives for the first period the differences 
Ar = + 254 cos 22 
1) From the period 1887—1891 alone we find 
= T— May 1 
Ar = + 274 cos An ————_... 
5365 
2) These figures will be published together with the second part of this paper. 
