Fonds consists of correspondence; photographs; and his long lost memoirs largely relating to his involvement in the 1837 Upper Canada Rebellion; and his interactions with such notables as William Lyon Mackenzie, Sir John A. Macdonald, Edward Barker, Pirate Bill and his daughter Kate, and a murderous Captain of the Fort Henry Guard.
Letters to two unidentified persons. It appears that one at least is to James Gow, Windsor. In it McLachan tells of family matters, books he has read and the support spiritualism has given him through talks with his dead son, John.
Fonds consists of a copy of "Robert Drummond: A Pioneer of the Rideau Waterway," a biographical article of Drummond, a lock builder on Rideau, and a shipbuilder in Kingston; and a copy of "125 Years of Physics at Queen's University, 1842-1967".
The fonds consists of a letter relating to Lord Dalhousie's visit to Perth in Upper Canada, and a newsclipping of an open letter to Lord Dalhousie regarding Wesleyan missionaries in Canada.
The fonds consists of nine letters relating to the foundation and early history of the library at Perth, Upper Canada, sponsored by Lord Dalhousie before his departure from Canada