Line of Position Navigation: Sumner and Saint-Hilaire, The Two Pillars of Modern Celestial Navigation

This book is a unique, concise resource for the history of the development of Line of Position navigation techniques from their invention in the 1840's to the end of the twentieth century. The point of crossing of two or three Lines of Position plotted on a chart quickly and accurately gives a fix of the navigator's position. We owe two nineteenth century navigators for the creation of the basic concepts of celestial navigation we still use today with modern GPS technology: Thomas H. Sumner, an American merchant captain; and Marcq Saint-Hilaire, capitaine de frégates in the French navy. This book describes the new techniques they derived from their personal knowledge and experience. It also includes a complete copy of the rare 1843 treatise by Sumner, formerly hard to find and very expensive, now available worldwide as part of this affordable e-Book.