March 2012 page 42
Peter I. Drinkwater
Tony Wood
John Moir

Readers’ Letters

This section features letters from readers discussing various sundial topics. Peter Drinkwater discusses dial transmission and an Islamic scratch dial. Tony Wood offers insights into the progress of "scientific" sundials. John Moir describes "Suburban Reflections" from his front garden.
How Sundials Work, Historical Dials, The BSS and Members

June 2012 page 46
Peter I. Drinkwater
Frank Coe
Sue Manston
David Harber

Readers’ Letters

This section contains three letters from readers. Peter Drinkwater discusses a Canterbury pendant, questioning Arnaldi’s gnomon positions. Frank Coe references a Chichester Sun Compass. Sue Manston points out a potential error in the 'waxing' and 'waning' engravings on the Balliol Moondial's gnomon, to which David Harber responds confirming the mistake.
Dials: Portable, Dials: Unusual

September 2012 page 6
Peter I. Drinkwater

Reader’s Letter

A letter speculating on the origins of the Hever Castle Dial, proposing it was a Sicilian-modelled Roman sundial made for a Northern European patron.
Sundial Design & Layout, Historical Dials

June 2011 page 36
Peter I. Drinkwater

The Ecclesiastical ‘Scratch Dial’ as a Serious Timekeeper

This article argues that medieval 'scratch dials' were serious timekeepers, not just symbolic. It describes their basic form, historical context of temporal hours, and connections to early Church observances and Islamic prayer times, asserting their utility at high latitudes.
Dials: Mass Dials, Historical Dials, How Sundials Work, Mathematics of Dialling

September 2011 page 37
Michael Lowne
Chris H. K. Williams
Peter I. Drinkwater
David A. Young

Readers’ Letters

This section compiles several letters from readers. Michael Lowne provides a complex formula for calculating shadow length from gnomon angle. Chris Williams praises Peter Drinkwater's article on scratch dials, linking them to medieval manuscripts. Peter Drinkwater responds on the transmission of scratch dial technology and the function of water clocks. David Young corrects a historical detail about BSS conference venues.
Dials: Mass Dials, Historical Dials, Mathematics of Dialling, The BSS and Members

June 1996 page 42
Peter I. Drinkwater

Dürer’s Melancholia I: A Diallist’s Dilemma

An analytical discussion of the sundial-like instrument depicted in Dürer’s ‘Melancholia I’, considering artistic interpretation and gnomonic function.
Dials: Unusual

February 1994 page 28
Peter I. Drinkwater

The Dialling Instruments Depicted in 'The Ambassadors'

Analysis of sundials and astronomical instruments in Holbein’s painting 'The Ambassadors', with insights into symbolism, usage, and historical context.
Historical Dials

February 1994 page 33
Peter I. Drinkwater

Curiosities of Dialling - Part 2, To Make Eccentric Sundials

Describes construction of eccentric sundials with non-standard hour lines and geometries. Focuses on design theory and practical outcomes.
Dials: Unusual, Mathematics of Dialling

June 1993 page 8
Peter I. Drinkwater

A Cold Look at Kratzer's Polyhedral Sundial

This article critically examines polyhedral sundials designed by Nicholaus Kratzer, Henry VIII's diallist, comparing his work with that of Oronce Fine (Francis I of France's diallist). It describes surviving and recorded dials, including those in Holbein's paintings, and questions the practical functionality of Kratzer's polyhedral design due to apparent geometric inconsistencies and the use of the Ecliptic's obliquity angle in extraneous constructions.
Dials: Multi Faced, Sundial Design & Layout, Historical Dials

June 1993 page 18
Peter I. Drinkwater

The Analemma of Vitruvius

This article explores Vitruvius's Analemma, a vital geometric construction from Roman architecture used for sundial design. It describes the step-by-step process of constructing the Analemma using only a ruler and compasses, explaining how it projects old Temporal Hours and can be adapted for modern hours. The text provides insights into ancient dialling techniques, their historical continuity, and potential links to medieval astrological traditions and later drawing methods.
Historical Dials, Mathematics of Dialling, Sundial Design & Layout

October 1993 page 42
Tanlaw
Peter I. Drinkwater
George P. Woodford

Letters to the Editor

This section contains letters from readers, including a discussion on "Neolithic Astronomy" and Stonehenge, suggesting early warning systems for climate change. It also features "Errors" pointing out misconceptions in a previous bulletin, and comments on "A Japanese Sundial", "Kircher's Sunflower Clock", and "Kratzer's 'Polyhedral' Sundial", along with a poem about rainbows.
The BSS and Members

February 1992 page 24
Peter I. Drinkwater

The Miracle of Ahaz

The article clarifies the Biblical account of the "Dial of Ahaz," explaining that the original Hebrew text refers to "steps" and a "staircase" rather than a sundial with "degrees." It discusses how medieval illustrations, like Holbein's, misinterpreted this, depicting a hemicycle-like device. The author also notes an adjustable Jewish hemicycle described in a 1650 translation, which could tell time by both the sun and the moon.
Dials: Hemispherical, Historical Dials

October 1991 page 31
Peter I. Drinkwater

Curiosities of Dialling

Peter Drinkwater explores historical methods of time determination, focusing on the "Shadow Square" and "Instrumentum Horarum" found on astrolabes and quadrants. He discusses ancient shadow scales, like those from Palladius, and how they were used to estimate time by shadow length, noting the practical, though often imprecise, methods employed by medieval laborers and pilgrims without modern instruments.
How Sundials Work, Historical Dials

February 1990 page 5
Peter I. Drinkwater

Inscriptions for Sundials.

This article delves into the history and interpretation of mottoes (inscriptions) found on sundials, noting that their extensive use became popular with the advent of "modern" scientific sundials in the 15th century. It explores various Latin and Greek phrases, often derived from scriptures or classical texts, such as "TEMPVS VMBRA" and "SIC TRANSIT GLORIA MVNDI". The article also discusses how sundials often provide the "Emblem" for common mottoes and the inherent ambiguities in translating Latin inscriptions.
Mottoes

June 1990 page 17
Peter I. Drinkwater

Understanding the Lambertian Circles

This article explains the construction and practical application of Lambertian Circles in analemmatic dials. These circles, plotted from a specific centre through the foci of the hour point ellipse, determine the times of sunrise and sunset for any given day, applicable across different latitudes.
Dials: Analemmatic, How Sundials Work, Mathematics of Dialling

October 1990 page 12
Peter I. Drinkwater

The Spherical Sundial

This article discusses various forms of spherical sundials, from simple painted stone spheres to the ancient concave hemisphere (Scaphe or Hemicycle) and the later, less effective, convex hemisphere. It also explores the projection of spherical coordinates onto a plane, linking them to the discovery of the analemmatic dial.
Dials: Hemispherical, Historical Dials, Dials: Scaphe, Dials: Armillary Sphere

October 1990 page 14
Peter I. Drinkwater

Minimum Length of Gnomon

This article addresses the calculation of a gnomon's length for a sundial, clarifying that it's about the ratio of the shadow-casting edge to the distance from the root of the shadow casting edge to the dial plate's edge. It critiques Mr. Sylvester's diagram, presents a pseudo-geometrical medieval method, and provides trigonometric formulas for calculation.
Mathematics of Dialling, Sundial Design & Layout

July 1989 page 12
Peter I. Drinkwater

Sun Time

Contrasts the "true" time indicated by sundials with the artificial time of clocks (GMT, BST) and advocates living in accordance with the sun's rhythm.
Equation of Time

November 1989 page 2
Peter I. Drinkwater

An Analemmatic Dial on a Vertical Plane.

The author explores applying the analemmatic dial principle to vertical planes, contrasting it with the more common horizontal version. The article provides the trigonometric calculations necessary for constructing such a dial on a vertical declining plane, detailing how to find the sub-style to meridian, the dial's "latitude," and the difference of meridians. It describes the layout process involving primary and minor axis circles to generate hour points and arcs for zodiacal signs, explaining why a movable gnomon is impractical for vertical planes and instead a horizontal rod is used. The dial is presented as a philosophical exercise, a functional piece for those interested in the Zodiac, or an aesthetic wall ornament.
Dials: Vertical, Dials: Analemmatic, Mathematics of Dialling