LATER EDITIONS:
The text is published in: J. J. Engel's Schriften, vol. 4, Berlin, Mylius, 1802, pp. 101-266.
Online text: Vol. IV

RECENT EDITIONS:
Reprint of the 1774 edition: Stuttgart, Metzler, 1964. (Facsimile) Edited by Ernst Theodor Voss.