CHRONOMETERS - Marine and pocket chronometers, pocket watches with tourbillons or carousels form, in the large family of clocks, a small group of very precisely running timepieces with little sensitivity to external influences, such as variations in temperature. In the text, the author takes up the fascinating development and history of the chronometer, portrays the most important manufactures in short biographies, and reports on the great voyages of discovery in the 18th Century that proved the utility of the chronometer as a navigational instrument. The illustration section, divided into five sections on the basis of historical and technical standpoints, portays some 350 items in the antique trade and at auctions or seen in private collections, with special emphasis placed on illustrations of their movements.