Clock

About 1330 in Italy was a striking clock in which the number of blows corresponded to each hour. And around 1475, was invented by a clock-spring plant. This led to the development of portable watches that were impossible for machines with weights.
Until the XVI century. Watches had only one hour, to an arrow. Share hours can be determined only approximately. It worked for most people. However, the astronomers needed more accurate recording of their observations. The result is a watch with minute, and some even with a second hand. Watch, which was regulated by the folio, was inaccurate, but the accuracy of the computation time increased significantly with the appearance in the XVII century the pendulum clock.