Collection Manuscript/Mixed Material Image 1 of Item 11. Letter from the Acting Yang DiPertuan Muda of Riau to Colonel William Farquhar. Resident of Singapore. written at Kampung Senggarang. Riau. 10 Ramadan 1234 (3 July 1819). Item 11. Letter from the Acting Yang DiPertuan Muda of Riau to Colonel William Farquhar. Resident of Singapore. written at Kampung Senggarang. Riau. 10 Ramadan 1234 (3 July 1819).