Sentence:  What is the centre of the earth? is it pure element only, as Aristotle decrees, inhabited (as Paracelsus thinks) with creatures whose <WSD>chaos</WSD> is the earth: or with fairies, as the woods and waters (according to him) are with nymphs, or as the air with spirits? 
Meaning of the word marked with <WSD> tags:  A given medium; a space in which something exists or lives; an environment.