Page 434 - 89 history of astronomy_opt

planets was established, the sun came to be
looked upon as a cause; and finally, early in
the seventeenth century, for the first time in
history, it began to be recognised that the
laws of dynamics, exactly as they had been
established for our own terrestrial world,
hold good, with the same rigid invariabil-
ity, at least as far as the limits of the solar
system.
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