Includes (formerly at p45): trigonometry notes, with small pencil drawing of a cleric on reverse, with annotation 'Sir R Ball, 13 Nov 1908' and 'Natural Sources of Power, R. S. Ball'; letter from T[homas] C. Fitzpatrick at Christ's College re Vernier division, 26 November 1901; notes by W. H. G. on "Colonel Everest" and navigational calculations, 5 June 1906; note on highest Red Sea water temperature; instruction notes re Hadley's Quadrant, 1731, on the reverse of Cambridge University Cruising Club headed paper; unidentified navigational calculations; trigonometry notes, 17 January 1907; printed map of 'The World on Mercator's Projection', London Geographical Institute; latitude and longitude (brief) notes. Also includes (formerly in the back of the notebook): hand drawn 'Table of equation of time' and associated drawings; notes on the loss of sight in a telescope.