Collection Manuscript/Mixed Material Image 1 of Item 24. Letter of the Tengku Pengeran of Siak to Colonel William Farquhar. 19 Jamadilakhir 1236 (23 March 1821). Item 24. Letter of the Tengku Pengeran of Siak to Colonel William Farquhar. 19 Jamadilakhir 1236 (23 March 1821).