《Tetrabiblos》Knowledge May Be Acquired By Astronomy To A Certain ExtentClaudius Ptolemy（Ashmand 英譯 1822）
In producing the changes of the seasons, the Sun itself is chiefly the operating and visible cause. There are, however, other events which, although they are not indicated in so simple a manner, but dependent on a slight complication of causes in the Ambient, are also foreknown by persons who have applied their observation to that end.
段落 tetra-1-knowledgem-23public-domain (Ashmand 1822)
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