181. Even now I am permitted to watch certain kinds of spirits, such as those who are fascinated by measurements and related matters, who by nature seem to be allured to studies of the Geometric sciences. Their imaginings, displayed to me, dwelt upon those studies, so as to correlate them all in a remarkable way with the category of measurements. They did not appear to me as evil. There was another kind of spirits who were boastful of themselves, yet who were not so bad, etc. etc., actually being only feelings [156, 178], who touch a person with a certain delightful pleasure - and if evil, are to be called Sirens.