"On the Optical Sense of Form"
Published as Über das optische Formgefühl: Ein Beitrag zur Aesthetik (Leipzig: Herrmann Credner), Robert Vischer’s doctoral dissertation, “On the Optical Sense of Form: A Contribution to Aesthetics,” marks the first use of Einfühlung as a noun. Exact month of publication unknown; if you have information about the correct date, please email felluga@purdue.edu with this information.
Articles
Rae Greiner, “1909: The Introduction of the Word ‘Empathy’ into English”