I wonder when was discovered the nine point conic. Wikipedia english article about it https://en.wikipedia.org/wiki/Nine-point_conic is misleading. The nine point conic wasn't discovered in 1892.
In the book Trilinear Coordinates, by William Allen Whitworth, published in 1866(https://ia801405.us.archive.org/21/items/trilinearcoordin029731mbp/trilinearcoordin029731mbp.pdf) we can see that the proof of the existence of the nine point conic is proposed as an exercise (page 473, exercises 438 and 439).
My rough guess is that the nine point conic was discovered in the very beginning of the nineteen century.
Any ideas?