A description of the lines drawn on Gunter's scale as improved By Mr. John Robertson, Late Librarian to the Royal Society; and executed By Messrs. Nairne and Blunt, Mathematical Instrument Makers, Cornhill, London. With their Use and Application to Practice, exemplified more especially in Navigation and Astronomy. By William Mountaine, Mathematical Examiner to the Honourable Corporation of Trinity-House of Deptford-Strond, and F R.S