Copy of letter to Professor Fletcher [unidentified] concerning an edition of James Johnston`s `Catechism of agricultural chemistry and geology`., 1862, MS.30013, folios 67-68. Papers of William Blackwood and Sons., MSS.30001-30984. National Library of Scotland Archives and Manuscripts Division. https://nlssb.as.atlas-sys.com/repositories/2/archival_objects/29187 Accessed September 24, 2024.