PearlyBooks

49 in stock

Attractively laid out on illustration-filled pages with texts that speak clearly to their subjects, these books review the technological achievements that have helped to shape history. Each book has between 70 and 110 photos, modern illustrations of historical events, and reproductions of famous illustrations from the past.Summarized here are ancient methods of timekeeping, including sundials and water clocks. The development of the Julian calendar, origins of names for days and months, and the assignment of number for each year are also explained. The development of highly accurate mechanical clocks in the eighteenth century changed methods of ocean navigation, exploration, and map-making. Modern time-keeping methods are reviewed, including speed-of-light measurements and atomic clocks.