[Letter] 1837 Aug 5, Philad[elphia] [to] Dr. R[obert] Peter, Lexington, Kentucky / E. Durand. [Discussing supply of English, Belgian and French journals and recommending apparatus made by Alva Mason. The letter is written on the reverse of the broadsheet catalogue and pro forma invoice, of 1837, of A. Mason, philosophical and chemical instrument maker, 24 Greenleaf's Court, Philadelphia]