The Works of John Playfair ...: With a Memoir of the Author ...

accuracy accurate afford ancient angles appear arch ascertained astronomical Board of Longitude bodies calculation cause circumstances computation considerable considered deduced degree Delambre determined discoveries distance Dr Black Dr Hutton Dr Simson Dr Stewart Dunkirk earth Edinburgh effect employed England equal equator error experiments extremely fathoms force France French geometer geometry give given gravity heat inequalities instrument investigation irregularities Jupiter known Laplace latitude length less longitude mathematical mathematicians matter means measured ment mentioned meridian method mixed mathematics moon moon's motion mountain Mudge nature nearly never Newton object observations orbit pendulum perpendicular philosophers planets Porisms principle probably problem produced Punnae quantity remark repeating circle revolution Robison Royal schistus seems side spherical excess stations supposed surface theodolite theorem theory thing tion toises trigono trigonometrical survey truth University of Edinburgh vibrations whole zenith