This volvelle piece in Richard Turner's A View of the Earth provides a way to calculate the times of day at different longitudes. This calculator paired with a time keeping piece such as a chronometer would aid in accurate navigation.

     Map making in the 1700s required a variety of talents. Because of the necessity for exactness, many map makers found issues such as parchment shrinkage troublesome. A map maker may begin drawing a piece of land they were in the process of surveying and find that by the same afternoon, their parchment had shrunk over the course of the day. This would miscue their measurements and scaling from when they originally began the map [1]. Other issues arose from putting the sheet of parchment or paper in the same position on a plain table as they were in when being previously worked on. In 1728 an improved plain table was invented, which was called the plotting table [2]. This table had clamps on its sides to hold in place the parchment or paper the map maker was working on. This technological innovation helped alleviate the issues of shrinking and shifting parchment [3].

     Other issues that arose in map making involve the actual surveying. Many surveyors experienced difficulty in obtaining accurate measurements. This miscued the distances between landmarks, contributing to inaccurate shaping of borders [4]. On land, the invention of Gunter’s Chain, comparable to a modern day tape measure, helped obtain more accurate readings of distance [5]. However, its limited length created difficulty in taking measurements at sea. The invention of the pendulum clock helped increase the accuracy of measurements at sea as it allowed surveyors to more accurately measure their distances and know their current longitude through the use of time keeping and trigonometric formulas [6]. The new time keeping pieces allowed for surveys over much larger regions than ever before [7]. In fact, during the 1700s, when the Turner text was written, entire continents were being mapped as seen below [8]. Even more accurate time keeping pieces, such as the chronometer, were invented during the 1700s and surveying distances became even more accurate [9].