Grantham's Hidden Gem - a Rarely Noticed Sundial

and even a few puzzles...

[All courtesy of and thanks to Clifford J Freeman of Castlegate Clocks, Grantham]

Image © Clifford J Freeman 2017, published with permission

About the Dial

As a result of an email exchange about SunInfo's pocket reference card "Solar Time to Civil Time Estimator" we have recently been made aware of this interesting dial which is in the one-time 'Clockmakers District' of Grantham at the junction of Welby Street and Westgate.  It was delineated by Charles Westwood in 1790 as a west declining dial that would also show the equinoxes and solstices.   It has only relatively recently been recorded in the National Sundial Register where its reference is SRN 6705. Unusually for such an old dial it still appears to retain its original nodus.  The design declination of the dial may be judged by the lie of the gnomon (more or less) along  the 2pm line at its latitude of (52 deg 55 min) - thus leading to the conclusion that the dial was designed for a wall facing almost exactly 30 degrees West of South. Further checks would be needed before this can be relied upon. [NB: For more about how to estimate this for yourself see this PDF: An easy way to estimate the declination of a vertical declining dial (5MB)].

Other images of this small but excellent dial have been received see below - that on the left was taken on the very day of the 2017 summer solstice at 1.27pm BST.  Click on the image to see a larger version. Note that the shadow of the upper edge of the nodus aligns with the summer solstice line; showing that this line is indeed correctly drawn and has been correctly restored. The image on the right is one taken nearly a year later, on 7th June 2018. It again shows the near-alignment of the nodus shadow with the solstice line.

 

Left image © Clifford J Freeman 2017, published with permission Right image © P.Powers 2018

 

The siting of the dial today can be seen from the ©Google Inc, 2017 'Streetview®' image below.  It can easily be appreciated why this dial took so long for it to be recorded in the UK's National Register!

©Google Inc, 2017 'Streetview®'

Analysis

1. Declination

It is always interesting to use Google Earth to make estimates of the heading of the wall in which a dial has been set.  The actual line of the wall is not of course visible in this case but measuring the line of the gable end and that of the roof line of the building both suggest that the wall in which the dial is mounted probably faces approximately 22 degrees West of South.

A sub-plaque declares that the dial was restored in 1968 by Frank J Webster but, perhaps surprisingly the restoration seems to have retained signs of earlier repainting drift; something which frequently attends old dials over the years. IIt is now known that in 1968 the building was a bakery and bakers shop. It was a very successful business. The owner and master baker was one Frank Webster. Did he restore the dial or did he contract someone else to do the job? A less than experienced dial restorer might explain the resulting 'limited' restoration.

The solstice and equinox lines, for example, are quite incorrect now and their zodiac symbols, as drawn, are also distorted.  However it is just this lack of restoration in these areas which rather suggests that the nodus might indeed be original.  Yet, the possible difference between dial's 'design declination' and the guessed wall declinations from Google Earth, might, if they prove true, suggest that the original dial might have been set canted slightly out to be at the design-declination of the dial* and that this may have been ignored when the dial came to be replaced or reset after the 1968 restoration when the restoration plaque was inserted.  We shall probably never know the full story but are trying to get more data...

* In earlier times dials were not always specifically calculated for a particular location. Instead precalculated templates of standard declinations were sometimes used and during mounting on the wall the actual dial plate was turned slightly (or canted) by trial to set the templated design to exactly what was needed for the particular location.

 

2. Equinox and Solstice lines

The equinoxes and solstices are, of course, the four turning points in the Solar Year and they are 'marked' by this dial. These events coincide with the Sun going into the appropriate astrological signs, with Summer Solstice (Cancer) at the bottom, Winter Solstice (Capricorn) at the top and the one line for the two Equinoxes Spring (Aries) and the Autumn Equinox (Libra).  As already mentioned the solstice and equinox lines on the dial today are incorrect.  A computer reconstruction of the layout for the original dial can easily be made and the figure shows this (for hour lines only) as produced by the excellent Sonne program.  The black dotted line along the 2pm line shows the centreline of the gnomon and the green square indicated shows one location for the nodus.

 

3. Other dial oddities

Inspection of the dial plate throws up a couple of interesting 'anomalies'. First of these is the reversal of the numeral marking the 9am line.  Whilst not common, these sorts of errors are not unknown in 18thC dials and so one would not rush to blame the restorer in this case.  A similar comment probably applies to the omission of the inter-numeral dot which is missing between X and XI.  There certainly is no obvious sign of there having being one originally.

4. The Motto

The motto of Non Redibo (I shall not return) is unusual and quite possibly unique in the UK. It is prefaced on this dial plate at the level of the date (1790) by the word 'San'. Why this should be is not clear. It might simply be that there was other text there which has since been lost or has otherwise gone unrestored yet the main part of this very motto is recorded by Mrs Gatty well before the identified 20thC restoration.   Indeed her reference to it (See the figure) actually mentions the very same location in Grantham and the date of 1790 so one might reasonably conclude that her entry relates specifically to this one dial!.  Her entry is further enhanced by text and a quotation attributed to Thos Ellwood.

The word 'San' is not mentioned by Gatty. Both Andrew James and Geoff Thurston have suggested that it might instead be a poor attempt at restoration of letters from the word 'Fecit'. After all it is on a level with the date. Indeed, as Geoff suggests, F.an 1790 might (just!) be an abbreviation of Fecit anno 1790.

[Note that the quotation that, in Gatty's Book of Sundials, follows the mention of the motto, is said to be taken from Thomas Ellwood's "To such as stand idle in the Market-place" and is, as Andrew James has pointed out, a 'Gatty embellishment' which is also mysteriously incorrect!
See the actual verse at 
http://tei.it.ox.ac.uk/tcp/Texts-HTML/free/K00/K003544.000.html#index.xml-body.1_div.6. One wonders whether the inscription might still be on a house in Westgate...

Although Ellwood’s sentiments and tone are very similar to Gatty’s “quotation”, her words are absent from his lines.]

Perhaps these unusual aspects are likely to be yet more things that we shall never know for certain about this dial.  Ideas to the Webmaster please!

11/06/2018

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