Manuscript Becker III.8.51, owned by the Universitätsbibliothek Leipzig, contains four fugues for organ or keyboard, from Friedrich Wilhelm Marpurg. They were copied from an unknown source by one J.A. Dröbs (if I read the insciption correctly). This Dröbs was not a very reliable scribe, as there are several obvious mistakes in the manuscript that is additionally often very difficult to read. The scores of these four fugues contain here and there some gueswork of what was actually meant and probably deviate in certain spots from Marpurg's original. As long as I do not have another source for these fugues however, this is for now the best I can do.
The second is a fugue in c minor. Curious in this fugue is that after the first exposition Marpurg develops a counter subject that is carried through the rest of the fugue and even lends the motivic material for the episode before the final exposition. Other than that oddity it is a well written fugue that is well worth the effort of practising it.
As with the Fuga in B Dur this fugue in c minor is notated in the manuscript on two staves. The voices are however several times quite far apart. Farther apart than I can play with hands alone. Even though the manuscripts states that these fugues could be played on keyboard as well, I think they are really meant as fugues for the organ, with full use of the pedals. The score is therefore renderen with three staves.
The recording was done with the Hauptwerk software and the sampleset, made by Sonus Paradisi, of the Janke organ in the Stadtkirche of Bückeburg (https://www.sonusparadisi.cz/en/organs/germany/buckeburg-janke-organ.html).
Score available here: http://partitura.org/index.php/friedrich-wilhelm-marpurg-fuga-in-c-moll
This is very reverent and beautiful. You play it so well. Nice sparing use of ornaments at the end there.