Another industry for which brass was found to have special advantages was the manufacture of clocks and subsequently watches. It is not known who made the earliest true clocks, but they extend back at least to the 10th or 11th Centuries. Their working mechanism was then extremely primitive with gear wheels either carved out of hardwood or made of wrought iron. Some of the earliest known true clocks were installed in Old St. Paul's (1286), in Canterbury Cathedral (1292) and in Exeter Cathedral (1300).
Clocks derive their name from the French cloche, doubtless because they included a bell which sounded the hours. Clocks with a striking mechanism appear to have been introduced in the 14th Century. There exists a very remarkable old astronomical clock by Giovanni Dondi, which, in addition to telling the time, shows correctly all the movements of the planets; it was made entirely of brass and copper. Time, itself, was apparently not of much consequence in those days, for Dondi took sixteen years to complete this masterpiece, from 1348 to 1364.
Early bracket or chamber clocks were almost invariably encased in gilt bronze or brass. The working parts were generally also of brass; and as glass was not used for clock faces until the 16th Century the dial was normally engraved on a brass face. A brass clock, made in 1632, was stated recently to be still in its original condition and keeping good time. Clocks have always exercised a fascination and many wonderful examples of the art may be seen in museums all over the world. Both the Wallace Collection and the Victoria and Albert Museum in London possess a number of priceless exhibits. Those in the Wallace Collection are mostly of the 17th and 18th Centuries and the majority are still kept working. The collection at the Victoria and Albert Museum is devoted mainly to watches and is perhaps the finest in Europe, but it also includes a number of remarkable old clocks (Figs. 22 and 24). The ornamentation on all these old clocks is lavish and in fact the great majority of the intricate chamber, bracket, lantern and other clocks that were produced up to the 19th Century had brass faces often engraved and chased.
 |
 |
|
| Figure 22. Brass and other copper alloys have been used in watch manufacturer ever since the first rather cumbersome watches were produced in Germany during the 15th and 16th Centuries. This example from South Germany, made during the 18th Century, is nearly 6 in. in diameter. | Figure 24. An ornamental German clock dating from the mid 17th Century. The case is gilt copper and the dials are silver. |
The earliest known watches were made at Nuremberg at the end of the 15th Century. They were large and ungainly; some, in fact, resembled an egg so much that they were called 'Nuremberg eggs'. Refinement in design gradually transformed them into the flatter and more practical form of later times.
One major improvement lay in the escapement, the first effective one being invented by Thomas Tompion (1639-1713). Graham, Le Roy, Earnshaw and Harrison were among the celebrated watchmakers who followed him. John Harrison (1693-1776), in particular, earned great fame by making his famous chronometer, and thereby winning an Admiralty prize of £2O,OOO in 1761. The immense value of the reward was due to the long-standing need for accurately ascertaining the time at sea, in order to determine the ship's longitude.
Harrison, who had begun as a Yorkshire carpenter's son, made a clock with wooden wheels while still a boy. He persevered with practical clock-making, and like others attempted to solve the longitude problem; his success came when he thought of the idea of an accurate Compensation-curb which would alter the effective length of the balance spring in proportion to the expansion or contraction caused by changes in temperature. His invention was given a very severe test. It was wound up and sent to Jamaica and back; on its return after several months, it was found to have lost only 1 minute 541/2, seconds. Harrison, like the other master clockmakers, worked in brass.