Following the invention of the balance spring by Christian Huygens in 1675, several interesting ,systems to show the minutes were conceived by watchmakers. In the six-hour dial, a single, centre-pivoted hand rotates once in six hours. The dial is divided from I to VI in Roman numerals. Therefore, starting at twelve o'clock, the hand has performed a complete circle by the time it reaches VI. Superimposed over the Roman numerals are a set of smaller Arabic numerals from 7 to 12. So from 7 to 12 the owner must read the Arabic numerals. Owing to there being only six hours, instead of twelve, to the full circle, the space between each pair is twice as large as on an ordinary dial. This gives enough room for a minute ring round the edge of the dial with two-minute divisions. Also, between the hour and minute rings is another circle divided into quarters and halfquarters. The time can therefore be read amount with considerable accuracy, although not without a good of practice for a modern owner, since none of the divisions appear in their usual positions. He must also decide whether he reading in the Roman or Arabic sector. Very few six hour dial watches of this period are known to exist, a fine one by Daniel Quare was part of the most selective Clutton Collection of important English watches.