《Tetrabiblos》Knowledge May Be Acquired By Astronomy To A Certain ExtentClaudius Ptolemy（Ashmand 英譯 1822）
The æthereal region, which philosophers call the fifth essence, encompasses, by its concavity, the elemental; its substance remains always unvaried, and consists of ten spheres; of which the greater one always spherically environs the next smaller, and so on in consecutive order.
段落 tetra-1-knowledgem-4public-domain (Ashmand 1822)
↗ 開啟公有領域原文（Wikisource）此段為公有領域典籍逐字擷取，零 AI 生成；原文亦存繁化前底本，可逐字審計。我們寧可少引、不可錯引——驗不過的引文一律捨棄。