Shewing the Causes which Formerly Obstructed the Advancement of Her Trade : on how Much Better Footing it Stands Now Than it Did Under Lewis XIV with Several Expedients for Raising it Still to a Greater Heighth [sic] : Containing, Among Many Other Curious Things, an Account of the Proportions of Gold and Silver in the Several Coins of Europe : a Comparison of the Revenues of Lewis XV. with Those of Several of His Predecessors : an Examination of the Course of Exchange Between Paris, London, and Amsterdam, for a Considerable Number of Years Together : Dissertations Upon Navigation and Commerce in General. The Necessity of France's Constantly Maintaining a Strong Naval Force. And, A Curious Plan for Enabling Her to Keep Up a Very Powerful Fleet with the Greatest Oeconomy and Advantage