Ref. https://www.youtube.com/watch?v=I9lpfY8w-CA 

Welte-Mignon historian and researcher Wolfgang Huller writes in
his unpublished book, "Unbekannte Pianisten auf Welte-Mignon"
(Unknown pianists on Welte-Mignon), that P. Khvostchinsky (1888-1920)
was an amateur pianist and composer:

  "Possibly identical to P.A. Khowotschinsky, Lieutenant of the
  Chevaliers de Garde, St Petersburg.  He is named in Welte brochures
  as a Russian customer of the Mignon.  Khvostchinsky recorded his
  own composition, a sonata, on 3 rolls for Welte Mignon.  It could
  have been a favor for a good customer."

MMDer John McClelland notes that the three rolls that comprise the
Premiere Sonate (2168, 2169 and 2170) were the last recordings made
in Russia before the recording equipment was shipped back to Freiburg.

(And preceding Khvostchinsky was pianist Gabriel Romanovsky who
recorded "Pictures at an Exhibition", rolls 2165 & 2166).  I now
suspect that the location of these last Russian recordings was not
Moscow but St. Petersburg, where Romanovsky was teaching.)

I found the sheet music at the Eastman School of Music web portal at
https://urresearch.rochester.edu/institutionalPublicationPublicView.action?institutionalItemId=22728 

The title page says:

  [dedicated to] Mladen Manuilovich Jovanovic
  P. Khvostchinsky
  Première Sonate pour Piano, Op. 7
  [publisher] P. Jurgenson,
  Moscou, Leipzig

No copyright is claimed nor is a copyright date given, which hints
that the composer paid Jurgenson to engrave and print copies for him.
Maybe he was actually Welte's "good customer"!

At https://en.wikipedia.org/wiki/P._Jurgenson  is a history of the
Russian publishing firm.

Robbie Rhodes
Etiwanda, California