Giovanni Francesco Zarbula

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File:Cadran solaire Saint Véran.JPG
1840

Giovanni Francesco Zarbula was a mural painter and sundial designer from Piedmont Italy who created a hundred or more vertical and vertical declining sundials in the French and Italian Alpes between 1830 and 1881.He worked exclusively in Savoy, in Piémont, the Valley of the Ubaye, le Queyras and around Briançon. [1]

Laying out the dial

Zarbula's method was one of observation then geometric construction. He did not need to know the latitude or declination of the wall, he did not use tables or calculations he just worked directly on the wall. All his dial were within 2° of the 45th parallel, simplifying the construction, and all gave five-minute accuracy.

  • With a plumb bob he drew a vertical line on the wall. This is the Noon Line.
  • He hammered a rod into the wall at right angles to the vertical. This is known as the centre of the dial, C
  • He observed and marked the shadow thrown by the tip of that rod, throughout a day. This line, technically known as a hyperbolic declination line.[lower-alpha 1]
  • Using a set of compasses, he determines the line of symmetry on the wall.[lower-alpha 2] This is the substyle line.[lower-alpha 3]

All the rest of the dial was laid out using a 45° square, with a 15° measure at the end. [lower-alpha 4]

  • He drew a horizontal line at a point of choice on the dial plate. This was the Horizon.
  • The square was placed on the substyle facing outwards, it is slid into any convenient position where it cuts the horizon, and he drew a perpendicular line drawn to that point. This line is called the equatorial. A line was drawn from that point to the centre of the dial; it was the 18h line (or 6h depending on the declination (d) of the wall). The points where the equatorial crosses the noon line and where the equatorial crosses the substyle line were important.
  • He placed apex of the square on the substyle line, so the sides passed through the equatorial points mentioned. (The 12h and 18h markers). The apex point is called the auxiliary equatorial centre.
  • A protractor or squares [lower-alpha 5] drew off 15° intervals on the equatorial. These were connected to the centre of the dial: the hour lines. The distance from the auxiliary equatorial centre to the equatorial formed the substyle height at that point.[2][3]
  • Zarbula-Hindu Circle.png
  • Zarbula-set-hourlines.png
  • Zarbula-auxiliary-equatorial-centre.png
  • Zarbula-set-hrs-on-equatorial.png
  • Zarbula-dial-face.png

The colours

Zarbula treated his paintings as frescos so the body colour was embedded in the supporting lime mortar. He didn't use organic pigments, just oxides. These do not fade in the strong alpine sunlight.

Existing Dials (cadrans)

Of the hundred dials by Zarbula, about 50 have survived, and a further dozen show visible traces.[4] In Hautes-Alpes, seven dials are protected as Historic monuments.[5]

His dials can be divided into three specific styles Öiseau (Birds), Geometric, Baroque. The birds that appear in the dials of the early 1840s include toucans, jabirus, parakeets and other exotic birds not seen in these mountains. The geometric works of the late 1840s and 1850s are noted or their simplicity, and contain a little trompe l'oeil to give the design some artificial depth. The baroque dials are contain birds, vases, full trompe l'oeil and false-marbling. They contain the symbols of the Second Empire (1852-1870) and Napoleon III particularly the Imperial Eagle. The dials produced after 1865 include the Masonic device of the Square and Compasses: this is co-incidetal to the rise and acceptance of masonry on both sides of the Italian French border.[6]

Commune/Village Lieu-dit/Hameau/Hamlet Édifice Region Country Date Protection Notes Coords. Illus.
Briançon Saint-Blaise Briançonnais France 1870 Deux cadrans Lua error in package.lua at line 80: module 'strict' not found.
Briançon Place d'Armes Centre d'art contemporain Briançonnais France 1876 Peut-être inspiré de Zarbula Lua error in package.lua at line 80: module 'strict' not found.
Briançon Saint-Blaise Briançonnais France 1870 Lua error in package.lua at line 80: module 'strict' not found.
Briançon Pont-de-Cervières, 4 chemin du Canal-du-Four Briançonnais France 1845 Lua error in package.lua at line 80: module 'strict' not found.
Cervières Maison Delouis Briançonnais France 1839 Mérimée PA05000001, Ministère français de la Culture. (fr) Deux cadrans Lua error in package.lua at line 80: module 'strict' not found.
Cervières Hôtel de ville Briançonnais France Lua error in package.lua at line 80: module 'strict' not found.
Eygliers Le Cros Briançonnais France 1841 Lua error in package.lua at line 80: module 'strict' not found.
La Salle-les-Alpes Les Pananches Chapelle Saint-Jean-Baptiste Briançonnais France 1879 Attribué à Zarbula Lua error in package.lua at line 80: module 'strict' not found.
La Salle-les-Alpes 38 rue de la Guisane Briançonnais France 1841 Lua error in package.lua at line 80: module 'strict' not found.
Puy-Saint-André Pierre-Feu Briançonnais France 1871 Lua error in package.lua at line 80: module 'strict' not found.
Puy-Saint-André Briançonnais France Lua error in package.lua at line 80: module 'strict' not found.
Puy-Saint-Pierre Le Pinet, 2 rue de Jérusalem Briançonnais France 1842 Mérimée PA00135605, Ministère français de la Culture. (fr) Deux cadrans Lua error in package.lua at line 80: module 'strict' not found.
Saint-Chaffrey Le Villard-Laté, 27 rue des Trois-Fontaines Briançonnais France 1847 Mérimée PA00135607, Ministère français de la Culture. (fr) Lua error in package.lua at line 80: module 'strict' not found.
Saint-Martin-de-Queyrières Bouchier Briançonnais France 1853 Lua error in package.lua at line 80: module 'strict' not found.
Saint-Martin-de-Queyrières Prelles Briançonnais France 1845 Lua error in package.lua at line 80: module 'strict' not found.
Saint-Martin-de-Queyrières Prelles Briançonnais France Lua error in package.lua at line 80: module 'strict' not found.
Saint-Martin-de-Queyrières Église Saint-Martin Briançonnais France Lua error in package.lua at line 80: module 'strict' not found.
Les Orres Le Mélezet Église Notre-Dame-de-la-Présentation Les Orres France 1853 Mérimée PA05000006, Ministère français de la Culture. (fr) Lua error in package.lua at line 80: module 'strict' not found.
Arvieux Le Coin Maison Jean-Paul Blanc Queyras France 1830 Superposition de cadrans, l'un d'eux pouvant être de Zarbula Lua error in package.lua at line 80: module 'strict' not found.
Arvieux Queyras France 1857 Lua error in package.lua at line 80: module 'strict' not found.
Arvieux Les Escoyères Queyras France 1842 Lua error in package.lua at line 80: module 'strict' not found.
Arvieux Les Escoyères Chapelle Saint-Roch Queyras France 1857 Lua error in package.lua at line 80: module 'strict' not found.
Château-Ville-Vieille Ville-Vieille Queyras France Attribué à Zarbula Lua error in package.lua at line 80: module 'strict' not found.
Château-Ville-Vieille Clot-du-Riou Queyras France Mérimée PA00135602, Ministère français de la Culture. (fr) Deux cadrans Lua error in package.lua at line 80: module 'strict' not found.
Château-Ville-Vieille Ville-Vieille Église Saint-André Queyras France 1843 Lua error in package.lua at line 80: module 'strict' not found.
Château-Ville-Vieille Ville-Vieille Queyras France 1843 Lua error in package.lua at line 80: module 'strict' not found.
Château-Ville-Vieille La Rua Queyras France Lua error in package.lua at line 80: module 'strict' not found.
Molines-en-Queyras La Rua Église Saint-Romain Queyras France 1849 Lua error in package.lua at line 80: module 'strict' not found.
Saint-Véran Les Forannes, la Pointe du Jour Queyras France 1840 Mérimée PA05000004, Ministère français de la Culture. (fr) Lua error in package.lua at line 80: module 'strict' not found.
Saint-Véran La Raux Queyras France 1840 Lua error in package.lua at line 80: module 'strict' not found.
Saint-Véran Ferme de Mathieu Romain Queyras France 1840 Lua error in package.lua at line 80: module 'strict' not found.
Saint-Véran Haut-Forranes Queyras France 1840 Lua error in package.lua at line 80: module 'strict' not found.
Saint-Véran Pierre-Belle Queyras France 1840 Lua error in package.lua at line 80: module 'strict' not found. 100px
Saint-Véran Les Gabelous Ancienne douane Queyras France 1858 Lua error in package.lua at line 80: module 'strict' not found.
Saint-Paul-sur-Ubaye Petite-Serennes Ubaye France 1860 Lua error in package.lua at line 80: module 'strict' not found.
Saint-Paul-sur-Ubaye Maljasset Ubaye France 1860 Lua error in package.lua at line 80: module 'strict' not found.
Pragela Souchères Basses Chapelle Val Cluson Italie 1872 Lua error in package.lua at line 80: module 'strict' not found.
Pragela Traverse, 6 via Nazionale Val Cluson Italie Lua error in package.lua at line 80: module 'strict' not found.
Pragela Villarmont Val Cluson Italie 1872 Lua error in package.lua at line 80: module 'strict' not found.
Sauze di Cesana Rollieres Chapelle Val Cluson Italie 1870 Deux cadrans Lua error in package.lua at line 80: module 'strict' not found.
Sestrières Champlas du Col, 28 via Nazionale Val Cluson Italie 1870 Lua error in package.lua at line 80: module 'strict' not found.
Sestrières Champlas du Col, 7 via Nazionale Val Cluson Italie 1870 Lua error in package.lua at line 80: module 'strict' not found.
Sestrières Borgata Val Cluson Italie 1872 Lua error in package.lua at line 80: module 'strict' not found.
Sestrières Borgata, 14 via del Colle Val Cluson Italie 1872 Lua error in package.lua at line 80: module 'strict' not found.
Sestrières Borgata, 12a via del Colle Val Cluson Italie 1872 Lua error in package.lua at line 80: module 'strict' not found.
Usseaux Balboutet Val Cluson Italie 1833 Deux cadrans Lua error in package.lua at line 80: module 'strict' not found.
Névache Ville-Haute Église Saint-Marcellin Vallée de la Clarée France Lua error in package.lua at line 80: module 'strict' not found.
Val-des-Prés Pra-Premier Vallée de la Clarée France 1843 Mérimée PA00135609, Ministère français de la Culture. (fr) Lua error in package.lua at line 80: module 'strict' not found.
Val-des-Prés La Vachette Vallée de la Clarée France 1840 Lua error in package.lua at line 80: module 'strict' not found.
Val-des-Prés La Vachette Vallée de la Clarée France 1852 Lua error in package.lua at line 80: module 'strict' not found.
Valloire Valloire France Lua error in package.lua at line 80: module 'strict' not found.
Valloire Les Verneys Valloire France Lua error in package.lua at line 80: module 'strict' not found.
Vallouise Maison de Bardonèche Vallouise France 1840 IM05003855 Deux cadrans Lua error in package.lua at line 80: module 'strict' not found.
Vallouise Le Villard Chapelle Saint-Sébastien Vallouise France 1869 IM05003852 Deux cadrans Lua error in package.lua at line 80: module 'strict' not found.
Valserres Les Trancs France 1854 Lua error in package.lua at line 80: module 'strict' not found.

References

Footnotes
  1. ↑ Declination of the sun ( δ ) not declination of the wall (d)
  2. ↑ Indian or Hindu Circle for Sub-style determination
  3. ↑ In dialling language substyle is used like sub aqua, meaning- under the style- not like subsection, meaning a smaller part. Similarly, equation means an adjustment and height can mean a perpendicular angle.
  4. ↑ Zarbula was working within 2° of the 45th parallel, so it worked. Further north or south the triangle would need to use the latitude and co-latitude and a protractor would have been needed
  5. ↑ A combination of a 30°/ 60° square, and 45° square could also be used.
References
  1. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  2. ↑ http://www.ens-lyon.fr/RELIE/Cadrans/Promenades/Zarbula/Equerre
  3. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  4. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  5. ↑ Mérimée Zarbula, Ministère français de la Culture. (fr)
  6. ↑ Lua error in package.lua at line 80: module 'strict' not found.

External links

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