How to Use the Pocket Sundial You will need:
A) A horizontal surface which is not close to any magnetic (or magnetizable) material.
B) To know the latitude of your location ( London is approx. 51.5 degrees North and Glasgow is approx. 56 degrees North) - but you don't need to be too accurate about this.
C) A bright sunny (not overcast) day! Note: this is not a quartz watch - at the very best it will give you the time to within a quarter of an hour. The time indicated will always be GMT not BST.
Procedure: i) Raise the latitude quadrant (the curved brass part marked 0-60) to the vertical position. ii) Raise the gnomon (the triangular-shaped brass piece) to the vertical position. iii) Tilt the hinged chapter ring (the circle with the Roman numerals) to your latitude using the latitude quadrant as your index. N.B. In the British isles this will only be slightly off the horizontal. iv) Place the instrument on the horizontal surface and orientate it so that when the compass needle comes to rest the "N" point (red) is over the North of the lower compass rose. v) The shadow of the gnomon on the chapter ring will give you the time. That's it!