Allamah Quhustani’s “Jami’ ar-Rumuz” could be downloaded from here:
This is an extremly rare edition, printed 150 years ago in Calcutta. A more common edition, is the Qazan edition, available from H.M.Saeed of Karachi.
The book does contain some weak views, which sadly have crept into the works of those after him, like the Hashiyah of Ibn Abidin, inspite of Allamah Ibn Abidin himself declaring the book unreliable! eg. the kissing of the thumbnails during adhan, the dua between every 4 rak’at of tarawih etc
[Mufti] Husain [Kadodia]