The Principles of Mr. Harrison's Time Keeper: With Plates of the Same is a book written by John Harrison in 1767. The book discusses the principles behind the design and construction of Harrison's timekeeping device, which was created to accurately measure longitude at sea. The book includes detailed descriptions of the various components of the timekeeper, such as the balance wheel, escapement, and pendulum. It also contains illustrations and plates that show the inner workings of the device. The Principles of Mr. Harrison's Time Keeper is a valuable resource for anyone interested in the history of timekeeping and navigation, as well as those interested in the development of precision mechanical devices.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.