The Sumner Line: Or Line Of Position As An Aid To Navigation (1919) is a book written by George Cary Comstock. This book is a comprehensive guide to navigation and the use of the Sumner Line, which is a method of determining a ship's position at sea. The Sumner Line is a navigational technique that uses the angle between the horizon and a celestial body, such as the sun or a star, to determine the ship's position. The book provides a detailed explanation of the mathematical principles behind the Sumner Line and how it can be used to navigate at sea. It also includes practical examples and illustrations to help readers understand the concepts. The book is aimed at sailors, navigators, and anyone interested in the art of navigation. It is a valuable resource for anyone who wants to learn about the history of navigation and the techniques used by sailors to navigate the open seas.This scarce antiquarian book is a facsimile reprint of the old original and may contain some imperfections such as library marks and notations. Because we believe this work is culturally important, we have made it available as part of our commitment for protecting, preserving, and promoting the world's literature in affordable, high quality, modern editions, that are true to their original work.