176 
That actually this difference in the method of registering exists 
between G. and Z. is confirmed by special observations, made for 
the determination of their relative personal equation, which is found 
to be positive in the sense G.—Z. 
The observers H. and Z., therefore, will be influenced in their 
registering by the velocity c.sec. J, with which the star approaches 
the thread, the observer G. will be independent of it. 
As it is always possible in zone-observations with differential 
reduction to limit the influence of the magnitude-equation by using 
different gratings, while in practice it is often necessary to take 
the range of the zones relatively large, it will always be desirable 
for an observer who is aware that he follows the first method of 
registration, to test his observations of transits for a dependence on 
the declination. Perhaps we may see in this result once more an argument 
in favour of the impersonal micrometer. 
Finally we give a table, which shows that the correction reaches 
quantities, which are by no means negligible. 
| 
Correction to the time of transit 
Mean decl. fund. 
ere | Decl. programst. | 
| | Observer H. Observer Z. 
| | | 
20° 10° —0s.011 | —0s.014 
20° | 15° — 0.007 | — 0.008 
20° 25° + 0.009 | + 0.011 
20° | 30° | + 0.021 | + 0.026 
30° | 20° — 0.021 = 0.026 
30° | 25° |: O2 — 0.016 
30° 35° + 0.015 + 0.019 
30° 40° + 0.035 + 0.043 
40° 30° — 0.035 — 0.043 
40° 35° | — 0.019 — 0.024 
40° 45° + 0.025 + 0.031 
40° 50° + 0.058 + 0.071 
July 1921. Leyden Observatory. 
