9 6 D O C .
22. Comment on the Preceding Note of
Albert von Brunn, “On Mr. Einstein’s Remark
about the Irregular Fluctuations of Lunar Longitude
with an Approximate Period of the Rotation
of the Lunar Nodes”
[Einstein 1919c]
Submitted 24 July 1919
PUBLISHED 31 July 1919
IN: Königlich Preußische Akademie der Wissenschaften (Berlin). Sitzungsberichte (1919):
711.
Herr von Brunn’s criticism is well founded. Since my error is not without a certain
objective interest, I too want to characterize it again briefly. My considerations
would be correct if the astronomers would use the earth as a spatial body of refer-
ence in connection with a special clock as a measure of time. In reality, the astron-
omers use the sphere of fixed stars as a coordinate system for spatial measurements,
and the earth’s rotation relative to it as a clock. Therefore, nonuniformity in the
rotation of the earth can only lead to errors in the measurements of time, as Herr
Brunn appropriately has pointed out.
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