The Great Red Spot on Jupiter

Abstract

WHEN this remarkable object came into striking prominence and attracted general observation in 1878, the rate of its rotation period was slightly increasing, and it continued to increase until the end of the century. Then in the early part of 1901 a large irregular spot appeared in the south tropical zone of Jupiter. This new feature, moving swifter than the red spot to the extent of about 23 seconds per rotation, soon affected the motion of the latter by accelerating its rate as it overtook it, and this influence has been repeated prior to the seven occasions on which the two objects have been in conjunction during the last twenty years.