title: VISUAL TIME SIGNALS FOR MARINERS BETWEEN THEIR INTRODUCTION AND 1947: A NEW PERSPECTIVE
abstract: The worldwide evolution of visual time signals for mariners during the period up to 1947 is explored in this paper. The emphasis is on their external appearance and how they were regarded by mariners for rating chronometers. The first accurate signals were established by the 1830s and the number of different locations increased steadily throughout the nineteenth century. The signals included time balls and time guns as well as many other devices under control by an astronomical observatory. By 1
journal: Journal of Astronomical History and Heritage