A set of loose pages dealing with problems in ascertaining latitude and longitude at sea by observation of the stars, with descriptions, computations and formulae referred to apparent time. There are also sections on finding the Moon's longitude from the nautical ephemeris [RGO 4/196: 1r], the motion of the Sun's image in a Hadley quadrant [RGO 4/196: 2r], and the testing of other people's hypotheses.
It is not known if the papers are foliated in their original order.