1873 Vischer

Robert Vischer
1847-1933 (German)
German Art Historian and Philosopher
"The projection of feelings into art work. He is credited with being the first to use the word Einfühlung to explain how we "feel into" or "in-feeling" of works of arts and nature in his work, On the Optical Sense of Form: A Contribution to Aesthetics, 1873. "

His father Friedrich Theodor Vischer had used a similar term

Stanford Encyclopedia of Philosophy
" Robert Vischer was the first to introduce the term “Einfühlung” in a more technical sense—and in using the substantive form he indicates that it is a worthy object of philosophical analysis—in his  “On the Optical Sense of Form: A contribution to Aesthetics” (1873). "

"Vischer’s use of Einfühlung (“in-feeling” or “feeling-into”) in his doctoral thesis (On the Optical Sense of Form: A Contribution to Aesthetics—1873) was the first mention of this word in this form in print. His more-famous father, Friedrich Theodor Vischer, had used the term Einfühlen in explorations of Idealism relative to architectural form, and related concepts were certainly already in the air. Indeed, the phrase "sich einfühlen" was used by Herder in the 18th century. Nonetheless, Robert Vischer’s exploration was the first significant discussion of the concept of Einfühlung under that precise name."