The letter was a appreciation for John Evershed discovery of spectral shift of light from the edge of the solar disc is really double of Einsteins's value. He mentioned about failure of Einstein's relativity. Further he provided 6 points on Newtonian principles, equation for the motion of a light, spectral shift of light.

This letter discuss about equation of a hyperbola and their work.

The title of the book " Theoric analytique du system du Monde" translates to " Analytical Theory of the World System ". There are two volumes of this book. The first volume has seven chapters, and the second volume consists of 9 chapters. This book was written by G De Pontecoulant and published in 1829.