1199 
star, have already been condensed into normal values by PiCKERING '). 
Caleulating the time of maximum light also from the mean devia- 
tions given by him, by means of a sine-formula, we obtain: 
Deviation = + 0702 + 07039 sin Ly + 254°) 
Phase Deviation Op Phase: -Meviation O.C 
042 +0701 (120) H07047 | 242 + 0M03 (123) -- 0™011 
i Ge SO doh Oe pe ay Ee OB (TTO == <4 NDD 
ened on (epee aes Oe 4 3.0 00-169) = 019 
ADE 7 lane DPS Se on Oe (169) == OTS 
1e ANS 26) EE Ob or lade: ee? Old 
The last column again contains the differences Obs.—Cale. The 
mean error of a nermal deviation is 07033. As a positive sign here 
means a greater brightness of Polaris, the maximum-light occurs at 
the phase 24.16 + 01.24. The zero epoch of the phase is at J. D. 
2400000 + 3.9683 /; for = 2073 this becomes J.D. 2408226.29, 
~ so that the normal epoch of maximum becomes 
J.D. 2408228.45 + 0.24. 
HI. 
Putting together the hitherto obtained results for the light-variation 
of « Ursae minoris and comparing them with the formula for the 
maxima given by H&RTzsPRUNG : 
J.D. 241 8985.86 + 3.9681 £ 
we find the following table: 
Year EK. Observed O—C Amplitude Observer 
24 
1879 — 2845 07696.57 + 0.14 — 0105 O0™056 vis. MürLer 
1881 — 2711 0822845 +0.24 +011 0.078 vis. HARVARD 
1894 — 1497 13045.81 + 0.08 + 0.20 - 0.057 vis. PANNEKOEK 
1910 QO 18985.86 + 0.08 0.00 0.171 ph. Hertzsprune 
1911 (+100) 18985.94 + 0.09 + 0.08 0.078sel. SrrBBINS 
Attempting to correct with these data Hrrrzsprune’s formula, 
we find (adopting as weights 2, 1, 4, 4, 4) as correction : 
+ 04.07 (+ 09.06) — 0.00001 (+ 0.00004) # 
Thus for the length of the period the exact value adopted by 
HERTZSPRUNG is found. The most probable formula for the maximum- 
epoch of « Ursae minoris now becomes: 
J.D. 241 8985.93 (+ 0.06) + 3.96809 (+ 0.00004) 4. 
1) Hoeven Gieten Nr. 174, Astronomische Nachrichten 4597 (Bd. 192, S, 219), 
78 
Proceedings Royal Acad. Amsterdam. Vol. XV 
