Letter from Augustus Heinrich Petermann, 47 Cranbourn Street to [Edward Sabine] Petermann thanks Sabine for ‘the copy of the British magnetic survey’. Intends to send Sabine a copy of the ‘little map’ when it is complete and has ‘at last’ finished two large maps of the British Isles. Refers to hydrographical maps. Petermann received a letter from Dr [William] Hooker. 13 July 1849