Dr David Richardson undertook a series of missions whilst Assistant Commissioner in the Tenasserim Provinces (including modern-day Thailand and Myanmar). This material includes some of his journal of his mission to Siam, and a report and letters to E.A. Blundell, Commissioner in the Tenasserim Provinces.

Letter from David Richardson to E.A. Blundell to send a report on the information in his possession concerning the "outrage committed by the Laos [Shous] on their Birman frontier". He begins his account with information dating from 1837 and gives a report of the politics that he knows about the area. He reports on the different chiefs and their interactions. The letter is dated August 31st 183[9]. It appears to be a draft as it contains corrections and annotations.