bestowed upon weights and wheels and escapements and balances. A century of experimenting resulted in a clock without a weight (Fig. 9). In this timekeeper you recognize the beginnings of the modern watch. The uncoiling of a spring drove the machinery. Instead of the balancing beam with its weights as in De Vick's clock, a _balance wheel_ is used. The escapement is the same as in the first weight-clock. The busy and delicately-hung little balance wheel in your watch is a growth from De Vick's clumsy balance beam. The spring-clock would run in any position. Because it could be carried about it led almost at once to the watch. Many places claim the distinction of having made the first watch, but it seems that the honor belongs to the city of Nürenburg. "Nürenburg eggs," as the first portable clocks were called, were made as early as 1470. The first watches were large, uncouth affairs, resembling small table clocks but by the end of the sixteenth century small watches with works of brass and cases of gold or silver were manufactured (Fig. 10). [Illustration: FIG. 9.--A CLOCK WITHOUT WEIGHTS.] [Illustration: FIG. 10.--A WATCH OF THE 16TH CENTURY.] [Illustration: FIG. 11.--GALILEO'S PENDULUM. (1650.)] The last important step in the development of the clock was taken when the _pendulum_ was brought into use. The history of the pendulum will always include a story told by Galileo. This great astronomer, the story runs, while worshiping in the cathedral at Pisa one day, found the service dull, and began to observe the swinging of the lamps which were suspended from the ceiling. Using his pulse as a timekeeper he learned that where the chains were of the same length the lamp swayed to and fro in equal length of time, whether they traveled through a short space or a long space. This observation set the philosopher to experimenting with pendulums of different lengths. Among the many things he learned one of the most important was this: a pendulum thirty-nine inches in length will make one vibration in just one second of time. Now, if the pendulum could only be kept swinging and its vibrations counted it would serve as a clock. Galileo, of course, saw this, and he caused to be made a machine for keeping the pendulum in motion (Fig. 11), but he did not make a clock; he did not connect his pendulum with the works of a clock. This, however, was done about the middle of the seventeenth century, although it is somewhat difficult to tell who was the first to do it. The honor is claimed by an Englishman, a Frenchman, and a Dutchman. The truth is, clockmakers throughout Europe were trying at the same time to make the best of the discoveries of Galileo, and several of them about the same time constructed clocks with pendulums. The one who seems to have succeeded first was Christian Huygens, a Dutch astronomer, who, in 1656, constructed a clock, the motions of which were regulated by the swinging of a pendulum (Fig. 12). The weight was attached to a cord