This version will change the slides on a mouse click. It can be set to cycle continuously in ‘Slide show’ ‘Slide transition’. Most slides contain animated captions and diagrams. For presenters using ‘mouse click’ control a small blue dot will appear bottom right when each slide is complete Note for Presenters Begin presentation on Slide 2 Press ‘Escape’ or ‘Esc’ to end show.

© Tony Moss 2006

All of the material in this presentation originates from the work of Edward Cholmondeley Middleton of Birmingham, England as published in his 1913 instruction book. A facsimile of this typewritten work has been published by NASS

I must record my thanks to Mac Oglesby (NASS) and Mike Shaw (BSS) for many sessions of patient proof reading, additional material, valuable suggestions and encouragement.

PowerPoint™ is not a precision drawing program. It is not always possible to position lines and points with total accuracy Any small inaccuracies in the following slides are mainly due to this fundamental problem. The delineations described take no account of longitudinal correction. The dials would therefore indicate apparent solar time.

This presentation was inspired by the section on the Middleton Dialling Scales in Frank Cousins’ book ‘Sundials - the Art & Science of Gnomonics’ To assist understanding and to avoid confusion the same terminology has been adopted in the slides which follow. H D (alpha) The angle between the substyle and the noon line. (phi) The latitude at which the sundial is located. (beta) The ‘dial height’ or angle between style and substyle. The hour angle of the plane of the gnomon. The declination of the dial. Negative east, positive West.

© Tony Moss 2006 The Latitude Scale The Hours Scale Scale divided into quarter hours and five minute intervals

12 6 a.m. Latitude 55° Delineating a horizontal dial for 55° North (morning hours) © Tony Moss 2006 Noon Line

12 6 p.m Latitude 55° Delineating a horizontal dial for 55° North (afternoon hours) © Tony Moss 2006 Noon Line

12 6 a.m. Co-latitude (35°) A vertical direct south dial for 55° North. (morning hours) © Tony Moss 2006 Noon Line

12 6 p.m. Co-latitude (35°) A vertical direct south dial for 55° North. (afternoon hours) © Tony Moss 2006 Noon Line

Style Height angle = 36.14° Substyle Line at ° to vertical. 90° to Substyle Line Plotting a Vertical Dial at 50° 30’ North Declining 22° West. (morning hours) Style Height ( ) = 36.14° Angle between Sub-style & Noon Line ( ) = ° Hour Angle of the Plane of the Gnomon Angle ‘H’ = ° = 1hr 50m 33secs. (by calculation) 1hr 50m 33secs 1hr Noon Vertical 50m 33secs © Tony Moss 2006

Style Height angle = 36.14° Plotting a Vertical Dial at 50° 30’ North Declining 22° West. (afternoon hours) 90° to Substyle Line Noon Vertical 2 9 mins 27 secs from end of scale hr m 0secs - 50m 33secs (H-1hr.) = 9m 27secs © Tony Moss 2006

Lindisfarne Dialling Scales available from Tony Moss The Lindisfarne Presse Dial House 43 Windsor Gardens Bedlington Northumberland In brushed stainless steel £25 per pair post free Heavy duty laminated paper £6 per pair post free.

A Jester Production 2006