In 1814 Terry invented what was called the "short-shelf clock," in which, by a change of arrangement and smaller weights, the pendulum being brought forward and greatly shortened and the weights being carried and run on each side, the whole was reduced to a more compact form. Clock and case were sold for a moderate sum. These clocks, like the tall-case ones, were made with wooden wheels, but after the introduction of rolled brass, machinery was invented by which blank wheels could be struck out with a die, the teeth afterward cut by machinery, and the brass-wheel clocks made cheaper than the wooden. This was about 1837.
The next improvement was substituting springs for weights. This had been done in Europe for two hundred years, but only with the most costly parlour clocks, and the springs were equal to the best watch-springs. Many kinds of cheaper springs had been tried without success, till a superior steel spring was invented in the United States, and the springs thus produced have for many years been sold at a price compatible with cheap clocks.
The wooden pendulum covered with gold leaf, which is one of the characteristics of a regulator clock, was invented by Silas B. Terry, a son of Eli. America has long taken a leading place in the making of clocks, and that desire to have the biggest and best which is characteristic of the youngest nation has influenced clockmaking.
For many years England prided herself on having the largest clock in the world. It is on the Houses of Parliament, London, and is known as the Westminster clock. Its dial faces measure 22 feet 6 inches in diameter. A larger one, however, has been erected during the past few years in Minneapolis, Minn., by an American clockmaker. These dial faces measure 22 feet 8 inches in diameter, and the Westminster clock has receded to second place.
Among extraordinary clocks which have from time to time been invented, none is more curious than that made in 1767 by David Rittenhouse, of Philadelphia. It has six dials; on the main one there are four hands which indicate seconds, minutes, hours, and days, giving one day more to February in leap year. Phases of the moon are also shown. The second dial shows the movements of planets about the sun; the third, the moon revolving about the earth; the fourth, the movements of Saturn; the fifth whether sun time is fast or slow with meridian time; while the sixth gives the combination of chimes which sound quarter hours, a choice of any one of ten tunes being played by pressing a knob on the dial.