"As for the Mystical Writers scrupling to Communicate their Knowledge, they might less to their own Disparagement, and to the trouble of their Readers, have conceal'd it by writing no Books, then by Writing bad ones. If Themistius were here, he would not stick to say that Chymists write thus darkly, not because they think their Notions too precious to be explain'd, but because they fear that if they were explain'd, men would discern, that they are farr from being precious."