Autograph letter signed by Colin Maclaurin containing a detailed correction of an earlier mathematical demonstration, 20 May 1738

Autograph letter signed from Colin Maclaurin addressed to James Stirling "at Leadhills", dated 20 May 1738, a detailed correction of an earlier mathematical demonstration, presumably that given in the previous letter ("When I spoke of concentric surfaces infinitely near I restricted only that I might distinguish the parts more properly into such as were convex and concave towards the particle"), referring to Cotes's theorems, encouraging Stirling's work on the figure of the earth ("I wish you had time to finish what you are doing", with two small mathematical diagrams.