An undated typescript copy of 'Draft of Instructions to the Officers acting as Principal Astronomers in the British Commission for defining the Boundary Line in North America under the Treaty of Washington' by G.B. Airy, 1843. The document includes sections entitled 'General Instructions'; 'Special Instructions'; 'To adjust a Transit Instrument'; 'To determine the Latitude by the Transit'; 'To determine the Latitude with the Altitude & Azimuth Instrument'; 'To determine the Sidereal Time, in a place whose latitude is known'; 'To determine the Latitude and the Sidereal Time in a place where neither of them is known'; 'Observations of Equal Latitude'; 'General Remarks on the use of the Sun instead of a Star in any of the preceding observations'; 'Remarks on some points to be noticed in the routine use of the different instruments'; 'Determination of the difference of longitude between two places at no very great distance apart'; 'Given the latitude of two stations and their difference of longitude: to find the bearing of one from the other'; 'Operations for finding the bearing of one point from another by survey'; and 'Observations for the Absolute Longitude of one station'. At the end is a letter from G.B. Airy to Captain Robinson R.E., 2 April 1843. There is also an accompanying photocopy of notes by J.E. Kennedy on the origin and provenance of the document.