First and only edition. A scientist known for his important research on electrostatics, also testified by a close correspondence with Benjamin Franklin and on operational geodesy, Beccaria was the main proponent of the scientific renewal of the University of Turin. In 1759 he was commissioned by King Carlo Emanuele III, an admirer of science and a great patron, to measure the arc of the Piedmontese meridian, the so-called Gradus Taurinensis in order to also calculate the equatorial circumference and update the Royal geographic maps. The distinguished scientist from Monregalese (Mondovì 1716 - Turin 1781) began the remarkable geodetic enterprise in 1760, assisted by his collaborator Domenico Canonica which required years of laborious counting, surveying and astronomical observations. This rare and famous work, published in 1774, a full 14 years after the start of the observations, describes the entire enterprise which was later remembered with two twin geodetic obelisks: one placed in Turin in Piazza Statuto called «Guglia Beccaria» and the another in Rivoli at the end of Corso Francia.