The principal part of the notebook is a transcription of a pamphlet by T. Clapp, late Professor of Valo College, entitled 'Conjectures upon the Nature and Motion of Meteors &c', dated 1781, in which Clapp discusses the appearance, velocity, direction, noise, duration of visibility, frequency of appearance, apparent size and equivalent energy of the explosive concussion of meteors, together with the air resistance encountered by meteors and the conjecture that the flames from meteors are caused by 'electric fire'. There are further notes by Lindley on the 'Determination of the Longitude of Paris by Mr Arnold's watches'. These are accompanied by records of the rates of the eight chronometers used when going to and coming from Paris - the final result, giving the longitude of Paris as 9m19s.8 east (2º19'57" east), is signed by Lindley and dated at the Royal Observatory, 5 October 1785. The volume also includes a calculation of the longitude of Lynn in Norfolk, and tables of the increase of sidereal over mean solar time and of the right ascensions of prominent stars.