An idealized picture of Stonehenge. The stones are aligned with the rising sun on Midsummer Day, assumed to happen at the top of the drawing. Stonehenge dates back to about 2600BC.

Shadow boards are still used in Upper Egypt for measuring the time taken to perform tasks, or for timing the distribution of water for irrigation. A water clock is used to mark the movement of the shadow.

A method of measuring the apparent position of the Sun (supposing, as always, that it's visible) is to use a shadow stick – or 'gnomon' – as a sundial.

Samuel Smiles tell the follwing story of George Stephenson, the railway pioneer, and his son Robert. While Robert was still at school, his father proposed to him during the holidays that he should construct a sun-dial, to be placed over their cottage door at West Moor. 'I expostulated with him at first', said Robert, 'that I had not learnt sufficient astronomy and mathematics to enable me to make the necessary calculations. But he would have no denial. 'The thing is to be done,' said he, 'so just set about it at once.' Well; we got a Ferguson's Astronomy, and studied the subject together. Many a sore head I had while making the necessary calculations to adapt the dial to the latitude of Killingworth. But at length it was fairly drawn out on paper, and then my father got a stone, and we hewed, and carved, and polished it, until we made a very respectable dial of it; and there it is…still quietly numbering the hours when the Sun is shining.' The Stephenson's sundial is there to this day; it is dated August 11^th MDMCCCVI (1806).

The interior of a watch, showing the escapement. The escape is controlled by the oscillations of the balance wheel, in turn controlled by the coiled hairspring. The action is reminiscent of the verge-and-foliot escapement. The pivots of the escape work are jewelled.