Another monumental clock is that in the clock tower on the Piazza San Marco, Venice. A Madmma sits on a platform between two doors overlaid with gold. When the time for certain religious festivals occurs, an angel collies out from one of these doors, blows a trumpet, bows to the Virgin, and passes out at the other door. The hour is struck by two giants.
Belfry clocks with automatons began to wane in popularity during the seventeenth century, and very few have been constructed since. House clocks with automatons were first made in the fifteenth century; hut the height of their popu larity was during the Renaissance, when won derfnl skill and great artistic talent were expend ed in their construction. A favorite design for these clocks was that of a ship, whose crew per formed numerous automatic functions. Perhaps the most beautiful as well as famous of these automatons is the ship-clock of Charles V. of France, now' in the Cluny Museum, This dock was irumnted upon rollers, on which its mecha nism caused it to advance and recede. Another favorite design was a mounted huntsman, who, at the stroke of the hour, moved his head and arms, while the head and tail of the horse also During the eighteenth century clocks with mechanically singing birds were popular. Within recent years automaton house-clocks have come to be regarded as interesting examples of mechanical ingenuity and skill, to be occasion ally produced and admired, rather than as neces sary or desirable articles of furniture.
The United States has produced its share of automaton clocks, though 'mist of them have been smaller than the great towe•-clocks of Eu rope. The 'Rittenhouse clock,' made in 1767 IT David Rittenhouse, of Philadelphia, has six dials, each marking off different astronomical events. The 'Columbus clock,' made by a citi zen of Columbus, Ohio, is 18 feet wide and I I feet high. Like the clocks already described, this one records many astronomical events; in addition, miniatnre figures perform various movements. Three towns of Pennsylvania— Donaldson, Hazleton, and Wilkesbarre — have possessed citizens who have added to their fame by their remarkable clocks.
In 1880 a clock was placed on exhibition in New York that was a striking illustration of the elaborateness to which clockwork may be It was the work of Felix Meyer, who spent more than ten years in its construction. The clock is 18 feet high, S feet wide, and 5 feet deep. It has 2000 wheels, rims by 700.pound weights, and is wound up once in twelve days. When the cluck is in operation, it shows the local time in hours, minutes, and seconds; the difference in time at Chicago, Washington, San Francisco, Melbourne, Pekin, Cairo, Constanti nople. Saint Petersburg, Vienna, London, Berlin. and Paris; the day of the week, calendar day of the month, month and season of the year, the signs of the zodiac, revolutions of the earth on its own axis and around the sun; also the phases of the moon and the movement of the planets around the sun. The ipla•ter-hour is struck by an infant, the half-hour by a youth, the three-quarter by an old man, and the hour by death, as in the Strasshurg clock. As the hour strikes, a figure of Washington rises from a chair and extends its right hand, presenting the Declaration of A door is opened by a servant, and all the Presidents, as far as and including Hayes, each dressed in the costume of his time. advance across the platform,
salute Washington, and retire through another door.
TowEn-CtocKs. As already pointed out: the earliest European clocks were all tower-docks —the house or `ehamber' clock being a later in vention, closely connected with the invention of watches. Among the early clock-builders, inge nuity and complication of mechanism. as dis played in the automatons, was considered of mire importance than accuracy as a timekeeper; but within recent years much scientific skill has been used to construct tower-clocks which, in spite of their enormous size and great height, with the accompanying atmospheric disturbances at so great a distance from the earth, shall still be accurate timekeepers.
One of the largest clocks in the world is the 'Westminster dock,' in the British House of Parliament, which was put in operation in 1860. Its four dials, situated 180 feet above the ground, are feet in diameter. Each minute-hand is 14 feet and the hour-figures on the clock arc 2 feet long. The pendulum is feet long. and weighs 700 pounds. There are 5 hells, weighing respectively 21 cwt., 26 cwt., cwt., 78 cwt., and 13 tons 11 cwt., for striking the first, second, and third quarters and the hour. These bells are hung from massive wrought-iron framing, in a chamber above the dial. The larg est. the hour-bell, popularly known as 'Big Ben: is 9 feet in diameter, and is by a hammer weighing 4 cwt., which is lifted 9 inches ver tically from the bell before it falls. This bell and the great bell of Saint Paul's Cathedral are tolled on the death of members of the royal family of Great 11ritain. In the 'Westmin ster clock,' as in all the tower-clocks formerly constructed, the mechanism which drives the clock is located in the tower directly back of the face. But in the city-hall clock erected iu Philadelphia in 1890 the clockwork is located in the main part of the building, and is connected with the dial-mechanism in the tower by means of compressed air. The whole is based on the fundamental principle of all modern mechanisms —the governing of great forces by compara tively feeble ones. The primary clock is an as tronomical clock, constructed with the greatest care, so as to be free from all disturbances from dust, moisture, and vibrations, and is so con structed that without interfering with its deli cacy and accuracy it can operate four sets of _ hands, each weighing o00 pounds. The dials are the largest in the world, having a diameter of 25 feet. The total height of the tower is feet, and the centres of the dials are 302 feet above the pavement. The hour-hand is 12 feet long, and is entirely different in shape from the minute-hand. so they never can lie mistaken. The face of the dial is made up of several pieces, and the usual numerals are omitted from the face, not being of service at so great a height. The dock was designed by Warren S. Johnson; a detailed description of its mechanism was written by him, and published in the Journal of Ow Franklin Institute (Philadelphia) for February. 1901.