SUNDIAL COMPASSES

This department only deals with portable sundials equipped with a compass. We describe in Part 1 the different types developed between the 17th and the 19th century.  You will find technical background information in the 2nd Part. Concerning the non-magnetic military sun compasses we recommend the excellent essay by Malcolm Barnfield The Sundial Goes to War on the website Sundials.

Pic. at left: Hunter-type sundial compass (manufacturer: Houlliot, c.1930).
Technical Data: Dia.: 2" / 50 mm; Depth (clsd.): 20 mm; Height (scales erected) : 2" / 50 mm.
(Click on the picture for enlarged view - see further down other Houlliot-made models)

In Nov. 1856, the French jeweller Edme POPARD who lived in Paris, rue Grenetat* n° 3 filed a "Patent" (no. 29,784) that would allow him alone to sell any fashion article featuring a sundial with a compass. This "patent" consists of a single short sentence that was completed (with many errors) in Jan. 1857 (see p. 2) : "... pour une nouvel [sic] application consernant [sic] le sistème [sic] solaire et de la boussol [sic] les deux réunis applicable sur les tabatière, pomme de canne, portemonnaie, bijouterie et tout [sic] autres articles de fantaisie ect. ect. marquand [sic] l'heure au soleil aussi exactement qu'une orloge [sic]."
(* reading in French language: horrible description by H. de Balzac in César Birotteau
Picture at r.: Patent (click on image for full view)

See other examples in the online collections of the Museum of the History of Science and of the National Maritime Museum.




CONTENT
Part 1 - Collection

- EUROPEAN DIPTYCH sundials (XVIIth C.)
- Modern sundials (XXth C.): U.S.A.: ANSONIA SUNWATCH and BOYD SUN-TIME; Austria: maker W.A.
- CHINESE sundials
- CRESCENT sundials
- EQUINOCTIAL compasses (Augsburg type)
- BION, Nicolas
- BUTTERFIELD, Michael
- MAGNETIC DIALS (PANTOCHRONOMETERS)
- GNOMON Compasses
L'ABEE-LUND'S WATCH COMPASS

Part 2 - Technical Information (incl. User Directions) and Bibliography

EUROPEAN SUNDIALS

IVORY SUNDIALS / FRANCE

These two-fold ivory sundials are called Dieppe-style because they were originally developed and mass produced by Charles BLOUD in the northern French city of DIEPPE (Normandy) from 1666 on. His brothers (or sons?) Gabriel and Jacques continued the trade and were first imitated by Ephraïm Sénécal, then by Jacques Sénécal (see table 2, center photograph.

Picture at left: ivory instrument, typical of Ch. Bloud's workshop although unsigned - France, 17thC.
Picture at right: User's instructions (dated 1653) incl. computing of the time by night (moon clock) and the high tide (facsimile available).

Table 1 - Detail views of the four sides
Table 2 - Various examples.

Tab. 1
COMPASS
Background: list of cities

(Pictures courtesy James Frellsen / Fleaglass)
CALENDAR


(...)
SUNDIAL


Note: pin gnomon is missing
LUNAR VOLVELLE
(night clock)


(see description HERE)

Some items feature many functions: Italian and Babylonian hours (see Definitions above), seasons curves and a latitudes table.
They have on top of the lid a universal dial and a polar dial. We find inside these sundials a vertical and a horizontal dial. Under the compass is also an analemmatical dial. This device is governed by a rotating disk with a perpetual calendar.

Tab. 2
Instrument with pendulum
(not signed)
Probably France, late 17th C.



Picture Jaypee (priv. coll.).


DIEPPE style sundial,
late 17th C. built by Sénécal
 
LIENHART MILLER
(Pic. at l.: Augsburg, Maximilian Museum, at r.: Vivielle's catalogue)
B/w pictures courtesy Cdt Vivielle's priv. coll.
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PORTUGUESE SUNDIAL

Wood, ink, paint (19th C.), signed I.S. i.e. Iohannes (Latin for Joao) da Silva.
The daylight hours are indicated for Portugal's mean latitude (38-39 deg.)



The words printed on the rear back face read 'VERDADEIRO AUTOR JOAO DA SILVA'
(Maker: Joao da Silva).

Note: This exhibit doesn't belong to the Online Compass Museum. These pictures were sent by a friendly visitor (priv. coll.).
North is indicated with a fleur-de-lis
but also EAST with two tiny symbols.
(go to MISCELLANEOUS / Cardinal points)


(Click on the picture for a detailed view of the compass).

Technical data
- Dimensions: 68 x 48 x 14 mm
- Weight: 33 gr
- Pendulum: lead bead
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SPANISH SUNDIAL

(Replica: go to Villa Alcor)
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CZECH SUNDIAL

Unsigned XVIIIth C. sundial with cardinals in Czech language*



s


Pictures courtesy Steinbrich-Fricke

(Click on images for enlarged views)

* S. Miscellaneous / Cardinals
Technical Data
- Dimensions: ... mm
- Pendulum: Lead
- Material: wood, ink,
- Date: 1748


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BRITISH SUNDIALS




Papered wood, early 19th C.


Note: This exhibit doesn't belong to
 the Online Compass Museum.
These pictures were sent by a visitor.


Reverse: List of towns by countries with their corresponding latitude but without clear order (neither alphabetical nor North to South).
Ex.: New York: 41, Philadelphia: 40, Boston: 42.


    

Item not signed, but the hidden hinge tabs and the check-mark shaped clasp hooks were only ever used by F. Barker & Son prior to 1875. 
The dial is also a very typical Barker dial.
(Pictures courtesy www.trademarklondon.com)
Technical Data
- Dimensions (closed) : 55 x 75 x 20 mm
- Material: wood (yew)



Side view of the clasp hooks
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GERMAN SUNDIALS

The two most important manufacturing cities in Germany were Augsburg (s. Equinoxial systems further below) and Nuremberg. In this city, sundial makers first produced diptychs made of ivory like in France (Dieppe) and later simple one made of paper and wood. A well-known manufacturer was Ernst Christoph Stockert (see picture at left courtesy Frederic Secchi). There still is a compass manufacturer called Stockert in Nuremberg (see also Marching compasses). Other German makers: Beringer, Kleininger etc.

Technical Data (item at left):
- Dimensions: 72 x 72 x 11 mm (2" 13/16 x 2" 13/16 x 0.433")
- Divisions: only the cardinal points are indicated (in German). The position of the magnetic needle corresponding to the declination in those days (late 18th C., i.e. approx. 15° west) is painted on the bottom. The gnomon automatically folds back. To read the time, one has to push down its lower end with one's thumb.
 

Papered wood,
early 19th c.



Note: This exhibit doesn't belong to the Compass Museum. These pictures were sent by a visitor.



Alphabetical list of towns in Europe with their corresponding latitudes.



Sundial with string gnomon
adjustable for 10 latitudes

 
On the rear side: List of European cities. Note: "OFEN" was German for Budapest
(Pictures courtesy James P. Frellsen)
Technical Data
- Dimensions: 4-1/16" x 1-1/2" x 21/32"
(103 x 63 x 17mm)
- Four hour scales



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Modern Sundials - U.S.A.

 SUNWATCH
First designed and manufactured by THE ANSONIA CLOCK CO., NEW YORK USA. (Patent June 6, 1922 by George HOLLINWOOD, THE ANSONIA CLOCK Co., 7th Av. 12th Street, BROOKLYN, NY) but the model was later retailed by Outdoor Supply Co. after ANSONIA was sold in 1929 to a Russian company (see the company's History).

There were 5 versions. Two for the American market, one for the Australian/New Zealand market, one for the British market and one for the Canadian market. The sundial base plate has 3 scales for telling time in 3 places with different latitudes. The inside cover has a chart listing 42 cities in the USA and their respective degrees latitude, longitude and clock time in minutes to add or subtract from sun time. The brass gnomon is fitted into a crevice in the base plate, to be pulled out when needed. The various latitudes are etched into the base of the gnomon for easy use. The Sunwatch is enclosed in a brass case with a push-button catch at the base (Source: Description by www.BONANZLE.com).
(Pic. abore: advertisement - click for enlarged view)


(Click on the picture above for a detail view of the dial)

Below: The latitude setting at the gnomon's base



Table in the lid: alphabetical list of towns (USA: from Atlanta to Wichita, UK & Ireland: Aberdeen to Wick) with additional data like variation, latitude, longitude incl. time correction in minutes, equation of time for each month of the year etc. 

User's instructions and box

Pict. sent by a priv. coll.
Click on the pictures for enlarged views



Technical Data
- Dimensions: 3" x 2" x 3/8"
- Compass diameter: 3/4"
- Adjustable blade-shaped gnomon: latitude setting on the side
- Latitude rings (depending on region): USA (South): 35-40-45 deg.
USA (North): 45-50-55 deg.
U.K.: 51-54-57 deg.
Patent's fig.: 30-40-50
- Declination setting range: +/- 40 deg.
- Brass case
- Built: 1920's
- Compass marked Made in France or Made in Germany

BOYD SUN-TIME
PROFILE - This system was patented in 1950 by Francis O. Boyd und John E. Johanson and manufactured by the JOHANSON MFG.  CORP BOONTON, NJ. (click HERE to view the patent's fig.). This item features e retailer of this item was the well-known Compass - Instrument and Optical Company, 268 Fourth Ave. New York 10, N.Y.


Above: the white element on top of the dial is the gnomon. It is to be orientated in such a manner that the crest doesn't cast a shadow on the flat base.

Below: the manufacturer's signature

The table of longitudes
above the sundial



Latitude setting



(Click on the images for enlarged views)


Map of the U.S. with the declination curves in red 



Declination setting
Technical Data
- Case Dimensions: 2" x 1 1/2"
- Compass diameter: 1 1/8" (30mm)
- Metallic case
- Sundial with two possible readings: Standard and Daylight Saving
- Table of longitudes for mainland U.S.A.
- User's instructions : 6 pages (facsimile can be ordered).

Concealed under the blue tag of Compass Instr. & Opt. Co.: "Precision Made By
Johanson Mfg. Booton etc..."
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Austria: W.A. (logo: sunrise)

PROFILE - Unknown manufacturer with the initials W.A. and a logo featuring a sunrise. The month names are indicated in Austrian German: Jän[ner] for Januar (January).
To read the time of the day, the instrument is to be held flat. Make sure that the 12 o'clock figure of the disk is facing the geographic (true) North mark of the compass. Turn the instrument until the needle's blue north end faces the tiny declination arrow (between 11 and 12). Place the gnomon bearing bar (missing on this item - see a sketch of a possible component HERE) onto the notches of the locking ring and erect the gnomon. Its shadow tells the sun-time at the location - not the exact time in the country!
The clinometer is used to measure the elevation angle of the sun or the moon etc. above the horizon by aiming at it with the two notches aligned.
Date of design/production: Magnetic North being indicated on the disk half-way beween the figures 11 and 12 and since 1 hour equals 15 degrees (360°/24h), the declination equals approximately 7 deg. west, i.e. 1910 for Austria's capital Vienna (result computed with the online programme of Canada's Natural ressources Dept.).
Note: This item's former owner added by hand corrections in red maybe to take into account some a change of location.



Bottom left: The manufacturer's initials and logo


The clinometer (90°)

Pictures courtesy M. Allouche 


The hour disks

Click on the images for enlarged views
Technical Data
- Diam.:  mm
- Thickness:  mm
- Hour Disks: 5, printed on both faces for 10 periods of the year
- The sunrise logo is almost identical to the Busch Rathenau's own logo


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CHINESE SUNDIALS

This description is far from being complete. See some general information in the category Nautical Compasses/China.
Further details are still missing. Thanks for sharing your knowledge with us.

- Horizontal Sundial with vertical pin gnomon (Reproduction - click on the link).

- Vertical Sundial (Diptych)



Click on picture. above for detail view of sundial and explanations of signs




The compass dial has no divisions. Only the needle's south half ist painted red.

Technical Data
Material: wood and paper, lacquered
Dim.: 75 x 65 x 21 mm


Calendar
- Centre disk: 12 month names
- Outer circle: "30" month day names




Both left and right sides are
covered with text.
Text: ?

Inclining Sundial

Description of the sundial panel and the compass's surrounding area based on the explanation given in J. Klaproth's famous booklet Lettre à M. le Baron A. de Humboldt, 1834 (online HERE):
- The Adjustable Panel (sundial):
Above the gnomon: one illegible character; below the gnomon, the sign "bei" (north) and three concentric circles :
  • Inner circle: the 12 signs cycle
  • Middle circle: figures 1-12, repeated twice, clockwise.
  • Outer circle: (?)
- The Compass's surrounding Area (three concentric circles):
  • Inner circle: the eight kua or trigrammes of Fou Xhi (compare with the instruments displayed in the category RELIGION).
  • Middle circle: the same in classical characters (N-W in red).
  • Outer circle: the 24 Tcheou cycle (see cat. NAUTICAL compasses).

Technical description - Inclining sundial - The compass has a grey metal base on which the meridian line is marked. It has a steel needle, reddened at its South end, and is covered by a glass plate, held in place by a black ring. Beneath the hour-plate is a toothed ratchet scale with 13 divisions, marked in black. A brass strut attached to the back of the hour-plate is set in this scale to position the hour-plate. The front has an hour scale for Chinese hours. Two red characters within this scale indicate that the compass should be turned to the North. There is a brass rod gnomon that folds flat when not in use, to be set perpendicular to the hour-plate. On the reverse side of the dial are nine Chinese characters (three in red) giving the name of the maker and the area from which he came.



Technical Data
Material: wood and paper, lacquered
Dimensions: 120 x 58 x 18 mm




On either side of the notches, probably city names. Additionally, four signs in red ink


Rear side:
- three signs in red
- six signs in black
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CRESCENT SUNDIALS

This instrument is signed by J[oseph] Jackson who was working between 1735 and 1760. It was probably manufactured in about 1750, this assessment being based on the style of engraving.
Principle: Maker's or user’s instructions for sundials of this type are not known to exist. Basically the crescent gnomon has to be adjusted to the latitude of the place where it is being used. An adjustment is also made for the time of year, using the calendar scale, and the instrument is levelled using the levelling screws and spirit levels. Normally these kinds of dials do not have a compass, being regarded as self-orienting, since if the adjustments mentioned are made, the shadow of the tips of the crescent will fall on the hour scale and the instrument can simply be turned until this happens. Possibly the addition of a compass was so that the magnetic variation could be checked against a noon reading. Examples by English makers are rare, as this design never seems to have been as popular in the British Isles as it was in continental Europe.
(Source: Gloria Clifton, The Royal Observatory, Greenwich, UK)

The exact function of all parts cannot be entirely described. Your help is needed.

Crescent sundial signed
J. Jackson, London
(c. 1750)



Technical Data
Dimensions:
12" across x 10" 3/4 tall

Ad for a/c avionics instr.

View from aft



Detail view of the calendar around the base plate



(Click on the images for enlarged views - All pictures courtesy Scott Meyer)
Detail view of the compass dial. The needle's pivot straddling on top of the central level tube is a unique feature.



The maker's signature and angle values


The crescent-shaped hours scales (top ends)


Detail views of individual scales

Hour scale (minutes):


Zodiacal signs


The vernier on the latitude scale


The months scale on the gnomons holding crescent

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EQUINOCTIAL COMPASSES

TECHNICAL DESCRIPTION (for USER'S INSTRUCTIONS see Part 2, bottom)
(Note - An equinoctial sundial in a hunter-type pocket compass case is displayed at page top).

This system is assumed to have been developed in France in the late 17th C. by a clockmaker living in Auch (South of France) called Rugend. Like many others, he was forced to emigrate to Germany because of the religion wars and maybe changed his name into Rugendas since we find compasses made in Augsburg which are signed Rugendas.
(Quoted after Mesures du temps et de l'Espace - OLF, 1970)

The typical Augsburg dial consisted of an octagonal or square base with a large compass set in the centre. The equinoctial ring of the dial was hinged to the base plate and its gnomon was a narrow rod set at the centre of a pivoted bar lying across the West-East diameter of the hour ring. The latitude of the hour ring was set by means of a latitude arm hinged to the base plate, against whose scale the angle of the equinoctial ring could be set. The latitudes tables were generally engraved on the underside of the compass bowl but sometimes printed on a paper glued inside the lid of the box.

The magnetic declination was sometimes indicated with the letter E (emendor) on the dial of some compasses like this Vogler sundial (see pic. at left - courtesy James P. Frellsen - click to enlarge). Since the declination was approx. 10° East in the late 18th C., the E-E line indicates the magnetic North-South axis.
Note: The cardinals are indicated in Latin Language. S = Septentriones = North!

We display below two typical items: A mass-produced Vogler and a high-quality Joseph Anton Schöner.
Andreas Vogler was the brother of Johann Georg Vogler who had started a shop in Augsburg in 1740. Andreas took the business over at his brother's death in 1765 and continued until the 1790's. He died in 1800. They had specialised in poorly executed, cheap mass production items with crude design and little accuracy.
(Source: Higton, H. - Sundials – an Illustrated History of Portable Dials © 2001)

Picture: print out of
La GNOMONIQUE pratique
, Fig. 68



(Click on the drawing for an enlarged view)
German pocket instrument 



(Picture courtesy Jaypee - Click on the picture for an enlarged view)


Reverse: the latitudes of a few cities* and Andreas VOGLER's signature abbreviated "And. Vogl".
Eleva Poli = Elevatio Poliarum (latitude of cities)
Augsburg Paris 48, Cracau (Kracow), Prag (Prague) 50, Leipzig 51
Luxurious gilt instrument
View from the side
(hour ring fully erected for the photograph)




Pictures courtesy Efim Tulchinsky -

Click for enlarged views
Top view showing the maker's signature: Joseph Anton Schöner


The dial features cardinals in Latin language (see Miscellaneous / Cardinals / Latin)

The pendulum ensuring an horizontal position:

City names on reverse:
- OFEN is the old German name of Budapest. Pest is the Hungarian form of the former slav name Pecs meaning "oven". This was probably the safe place on the other bank of the Danuve river where the city's bread used to be baked.
- St Maura was a fortress near Istanbul
(picture copyright www.vintage-maps.com)
Other names: Ceftalonia, Spalatro: see WIKIPEDIA
Note: A dash was engraved above a letter in the place a following "n" or "m" (like in Dresde-n, Amsterda-m and Cölle-n = Köln/Cologne) left for place reasons.




Other equinoctial compasses




High precision instrument with two levels and three levelling screws made by F. BARKER & Son (1919).

The latitudes scale reaches from zero to 90° so that this instrument can be used from the equator to the poles.


Instrument with one level sold by SECRETAN (ca. 1930) but probably made partly by Houlliot (dial and needle)



Instrument built by HOULLIOT
in the middle of the 20th c.

F. BARKER & Son (1880)

Pictures courtesy TML
Technical Data
- Dia.: 52 mm
- Weight: 108 gr
- Silvered dial and scales
- Balance weight on bar needle for adjustment to local dip
Views of dial and chapter ring



Made for Lawrence & Mayo

(Click on the images for enlarged views)
HOULLIOT (1930)


Technical Data
- Diameter: 2" / 50 mm
- Depth (closed):  20 mm
- Height (chapter ring erected): 50 mm
- Weight: 90 g
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BION

PROFILE - Nicolas BION (1652-1735) was a French mathematician. His shop was located in Paris, Quai de l'Horloge du Palais.
He wrote a famous book on mathematical instruments called Traité de la construction et des principaux usages des instruments de mathématique and built Butterfield-type compasses.

WARNING - Beware of FAKES! (click on link for pictures)
Several major museums have confirmed that contemporary reproductions are currently available - usually on eBay. These are only worthless museum gift shop items and not original antique items. You can easily recognize them by the gross engraving of the latitudes (40-50-60) on the gnomon's adjustable blade. Send us pictures if you are unsure.

  

N. BION showed in his book a sundial with his name as the maker on page 362.

Picture courtesy T. Kloss
A drawing (flower or landscape) was engraved on some Bion dials' rearside
Note: the needle and 2 screws on this compass are not genuine!


Descr. in a 1984 auction catalogue
Transl.: Butterfield-type sundial signed N. BION. Late cXVII - early cXVIII. List of 24 French, Italian and European cities located between 40 and 55 deg. north.
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BUTTERFIELD

PROFILE - Michael Butterfield (1635-1724) was a British clockmaker who settled in Paris about the year 1663. He worked for the royal court of France and was appointed engineer to the King. He opened in the district faubourg Saint-Germain, in the street rue Neuve-des-Fossés, a shop for precision instruments. His shop's sign read AUX ARMES D'ANGLETERRE (at the sign of England's coat of arms, 1st mention in 1677). Russia's Czar Peter the Great visited his shop in 1717 and ordered a great quantity of dials made of gilt copper. After Butterfield's death in 1724, the sun-watch type he had been manufacturing and selling was copied by many european manufacturers.

Description
The Butterfield dial is a type of semi-universal horizontal dial, that is, a horizontal dial which can be used in a number of different latitudes, but not in the full range from 0° to 90°. It is generally either octagonal or oval in shape and is almost always marked with three or four different hour scales, each of which is marked with a specific latitude. The essentials of the Butterfield sundial are a dial plate engraved with a number of different hour scales serving different latitudes, a compass, and an adjustable gnomon. The gnomon is marked with a latitude scale and it can move within the bird index which marks the latitude angle against the scale. 

It was not B. who originally designed these instruments. Examples are known which clearly date from before the time that Butterfield began working in Paris. Earlier items known were made by Roch Blondeau (dated 1673), but also by Timothée Collet.

The fact that Butterfield used a bird-shaped pointer on the gnomon probably made his sundials highly fashionable and he soon achieved a monopolistic situation on the market.

(Source: Higton, H. “Sundials – an Illustrated History of Portable Dials” © 2001)



Picture excerpted out
LES MONTRES SOLAIRES (1932).


(Click for enlarged view)

The typical blade gnomon with latitudes scale and the bird's beak shaped pointer.
NOTE: On this drawing, the latitudes scale is inverted by error: 60° should be at the lower end and 40° at the top!


Description and user's instructions for a Butterfield-type sundial (4 p., French, signed by Lasnier, 1751). Facsimile and comments can be ordered (SHOP).

Pictures below: Late 17th, early 18 Century silver horizontal "Butterfield Sundial"



Butterfield's signature is
engraved on the upper side.

All pictures by Ottavio Veglio
(Click on the pictures for enlarged views)


The inscription "Premier Cadran" (1st chapter ring) means that the inner chapter ring is valid for the cities written in the disk. Engraved on the reverse side are the names and latitudes of some 20 European cites.


Technical Data
- Dimension (length): 2-1/8 inches, 54 mm
- Material: silver
 

The latitudes scale is only visible on one side of the gnomon. The other side is often engraved with acanthus leaves.

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MAGNETIC DIALS (Pantochronometers)

Description
A pantochronometer is a Horizontal Magnetic Dial. The rotating card is automatically pointing to the magnetic pole. This system was already in use in the 18th C. Collectors & museums refer to pantochronometers as "Magnetic Dials". The term, "pantochronometer" meaning combined Sundial & Compass, was first used late 18th century, early 19th century, probably in the UK, possibly by Essex & Co (Charles Essex ? 1824-1828, London) 19th century versions. Most makers referred to, or labeled them as, "Magnetic Dial" {Porter for example}. Few others referred to, or labeled them as pantochronometer, usually, but not always, with EOT tables (Equation of Time). 

Magnetic Dial Problems
- The usage is limited to the latitude determined for the dial.
- Declination / variation could not be altered/adapted. All sundials must be oriented to TRUE NORTH, never magnetic north. When made, declination / variation values would be applied to the card. Over time (less than 10 years) declination / variation values shift (either west or east) thus rendering the dial inaccurate.



Pictures courtesy weezie24

Technical Data
- Dia.: 57 mm
- Height (without lid): 37 mm
Maker: Stockert, Germany, late 18th C.
(probably Johann Paul - see also above German sundials)


(Click on the pictures for enlarged views)

PROFILE - ... (C. R.) was a French sundial maker ... ?




Technical Data
- Diameter: 55 mm
- Depth (with lid on): 20 mm
- Weight: 34 gr
- Material: Gilt light alloy
France, late 19th C.

(Click on the pictures for enlarged views)

(Click on the pictures for enlarged views)

Russian pocket sundial with domed glass

Technical Data
- Diameter: 40mm
- Depth: 14mm
- Weight: 18gr
- Early 20th C.
- Cardinals written in old Russian (compare with Miscellaneous / Cardinal points / Russian)


Picture courtesy private coll.
(Click on the pictures for enlarged views)
RÜTER UHR (watch) Type no. 5 - Berlin
Technical Data
- Dia.: 50mm / 2 in.
- Height: 25mm / 1 in.
- Materials: the gnomon, two adjustable magnetized razor blades and the disk were attached together with a pressure button and placed on top of a grammophone needle (click on link for picture, "Neues Universum").
- Manufactured: Summer 1946, shown in a weekly news (Wochenschau) footage.
Dwg. at left: Principle of the two hour rings for Winter and Summer hours (Winterzeit WZ and Sommerzeit SZ) and the magnetic declination scale. User instr. and techn. descr. in German available (s. SHOP).

HORIZONTAL POCKET SUNDIAL WITH ADJUSTABLE  GNOMON

PROFILE - C. R. (name ?) was a French sundial maker



Technical Data
- Diameter: 55 mm
- Depth (without lid, gnomon erected): 22 mm
- Weight: 35 gr
- Material: brass case, paper dial
France, late 19th C.

(Click on the pictures for enlarged views)

L'ABÉE-LUND'S Watch Compass

PROFILE - Johan Henrik L'Abée-Lund was a Norwegian engineer. He manufactured this compass from approx. 1922 to the late 30's.
The name Uhr-Kompass means "watch compass", and was meant quite literally:  It could be used as a sundial, with the use of the table on the backside. The red little ant was a part of a promotion gimmick. In these days every product should have a marketing slogan, and for this compass it was "Kjøp kompassen med Mauren i syd" i.e. "Buy the compass with the ant pointing south", referring to the well known fact that in the woods you can find approximately South by looking at what side of the trees the ants build their hill.
(Quoted from the website http://www.purgatory.net/kornelia/compass/compass.htm)
Picture at right: the south-pointing red ant


Picture r. bottom: On the case side is a scale reaching from 0-10 beginning at ESE (130°) and finishing at WSW (240°).

(Click on the pictures for enlarged views)



Technical Data
- Diameter: 50 mm
- Depth: 12 mm
- Weight: 65 gr

Below: The user instructions (4 p., Norwegian)

Pic. courtesy K. Takacs

FOLDING SUNDIAL WITH BINOCULAR

COMBINED INSTRUMENT: COMPASS (based on the sun's position) & BINOCULAR

Origin: Germany (ca. 1930-1940), model FAVORIT / D.R.G.M. (reg. trade mark).
Folding binocular with sundial. A device shaped like a bottle opener serves to lock in folded position the small spring loaded lenses.
User's instructions for the sundial-compass: The dial shows the hours of the longest possible summer day in Northern Germany (i.e from 3 in the morning to 10 in the evening) together with the cardinal points. To orientate the compass, one has to rotate the arrow so that the current hour (indicated by a watch) appears in the arrow's fork end. One turns then the compass with the arrow head pointing towards the sun. Example: at noon, the sun is in the South.
Like on all other opera glasses (shown in the category OTHER COMPASSES), there is a mirror on the face opposite to the dial.



Click on the picture for enlarged view of dial
Technical Data
- Length folded: 105 mm
- Compass Diameter: 40 mm
Indications on the dial:
- Sonnen-Uhr & Kompass (sundial and compass)
- Abends (afternoon)
- Morg. (morning)
- Tourist / D.R.P.a. (hiker)
Concerning the meaning of Tourist in German in those years, and the abbreviations, see MISCELLANEOUS / GLOSSARY.



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Pocket Hunter Sundials

Hunter type compass types with foldable Butterfield-type, bird-shaped gnomon. It appears in a 1932 catalogue of the French company S-L (see category Pocket Compasses) but was manufactured by Houlliot.


Picture of a similar model but with automatic needle lock actuated when closing the lid.



(Picture courtesy of Yuri Petrunin)
Technical Data
- Diameter: 45 mm
- Depth: 15 mm
- Weight: 49 gr
- Transit lock: manual

(Click on the pictures for enlarged views)



(Click on pictures for enlarged views)


Box compass - export model (Germany). The instructions for use are printed in the lid.
Manufacturer: Houlliot
 
(Pictures courtesy of Michel Collignon)

Pendant hold closed with the neck-lace chain


Replica of an antique instrument 

Technical data
- Dimensions: 50 x 38 x 13 mm
- Weight: 35 gr

(Click on the pictures for enlarged views)
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GENERAL INFORMATION about astronomy and sundial technique necessary to understand their functioning

The Physical Principle
A sundial is a reduced representation of the Earth. The sun's light rays impact the instrument exactly like the globe. This is why the sundial first has to be orientated. This can be done by means of the integrated compass but one must take the magnetic declination (the difference between Magnetic North and True North) into account. The gnomon (see definitions below) must point towards the Earth’s celestial pole – or – in line & parallel to the Earth's axis, towards the North Star* ... if one could see it during  the day hours!
On some dials bult in the18th c. the declination was indicated by means of a additional line between two letters E (for emendo = correction in Latin - see pic. at right).

 * The North Star and Latitude 
The angular height of the North Star {in degrees} above the horizon is the same as your latitude in degrees. The North Star is on the horizon at 0° latitude and not visible South of the Equator but even at 10° N. latitude {and below} the North Star may not be visible on even the clearest nights due to atmospheric haze.

The sundials' components

The Gnomon – Blade, Pin or String 
The hour is told by the shadow of a device called a gnomon. There are three different types:

- Pin Gnomons are fixed – whereas, blade and string gnomons can be fixed or adjustable. On fixed gnomons, the pitch or angle is the latitude at which the sundial was made. Sundials used at higher latitudes have a steep angle. Sundials used near the equator – or lower latitudes have a shallow angle.
- Adjustable Gnomons can range anywhere from 0° to 90° (example: Barker, above).
- String Gnomons - The string can be fixed for one mean latitude or adjustable (example: German sundial above).

Fixed Blade Gnomons usually have a simple hinge to lay them on the side when closed. Their slope is a mean value for a limited area (Mediterranean, Central Europe) and doesn't allow precise time telling.

Adjustable Blade Gnomons
Such gnomons generally consist of an adjustable quadrant engraved on one side of a folding hinged blade gnomon supported by a bird-shaped fitting (duckling). The dial chapter includes several (2-4) sets of engraved or painted scales alternating in Roman and Arabic numeral made for different latitudes. This sundial type is adjustable for latitude by increasing or decreasing the angle of the blade gnomon against the bird's beak . The shadow's border line on one of the appropriate dials for the different latitudes determines the actual time.

The compass
Pocket sundials incorporate a very simple recessed compass.

The Latitude Scale
On nautical or professional equinoctial compasses for explorers, which have to be usable in the entire world, the latitude scale must be representative of any location on Earth. It is thus graduated from 0° to 90°, covering a full hemisphere.
On pocket sunwatches, it just needs to cover the area in which it is intended to be used. The span typically measures hence only about 20 degrees in Europe (38-56 on the German compass above). This is enough to cover a zone reaching from Portugal to Scotland or 30-50 in the US (New Orleans to Quebec).
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TELLING THE TIME
Hour chapters are usually divided into 5 ~ 15 minute increments. Read left to right - from morning hours {4 am on the example at left} to afternoon hours {8 pm} with 12 (noon) typically in the middle (South). If a sundial is set-up correctly – the shadow cast by the gnomon onto the hour ring will give the time of day.
Note - Sundial Time is Different than Watch Time!
A sundial disregards time zones. These change every 15 degrees (time meridians), this value resulting from the Earth's circumference (360°) divided by 24 hours (one day or one Earth rotation). Sundial Noon is defined as when the Sun is directly overhead, not when a watch says it is noon. The difference here is the user's distance (east or west) from a time meridian {longitude}. This difference can be as much as 30 minutes if you are exactly between two time meridians. Since there are 1440 minutes in 24 hours, one minute equals (1440/360) four degrees of longitude (15 seconds per degree). The Prime Meridian or 0° longitude runs through Greenwich, the opposite, being the International Dateline at 180°. The full hour is thus only to be read at places located exactly on a multiple of 15° i.e. 30, 45, 60, 75, 90, 105, 120, 135, 150, 165 and 180 degrees west and east). Since the Earth (seen from above the North pole) rotates counter-clockwise, the sun apparently moves from east to west. Within a defined time zone, an observer has to add one minute per four-degree step to (or subtract from) the next "full-hour spot", depending on whether he stands west or east of this location i.e. before or after the sun traverses it at noon. Example: an observer located at 92° west longitude must add 8 minutes to sundial time to correct to clock time, Another one located at 88° west longitude would have to subtract 8 minutes.
Moreover, many time meridians follow the political borders of countries.
Another factor to sundial time is the Equation of Time where in some months of the year, time appears “fast” and in other months time appears “slow”, this being caused by the Earth's elliptical orbit around the sun.

Ancient Definitions of the Hours:
There has been several methods for counting the duration of a day:
- Judaic or antic hours: 12 hours from sunrise to sunset and 12 hours from sunset to sunrise. They were only twice in the course of the year of equal length, on March 22 and September 22 (equinox)
- Italic hours: 24 hours of equal length from sunrise until the next sunrise
- Babylonic hours: 24 hours of equal length from sunset until the next sunset
- Astronomical hours: 24 hours of equal length counted from noon until noon on the next day.
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USER DIRECTIONS 

A - Equinoctial Sundial
1} Place sundial on a flat level surface = parallel to the horizon (if applicable: acting on the screws to center the level bubble).
2} Set the latitude of the hour ring (example: London = 51°, New Orleans 30°, Toronto 45°).
3} Lift the gnomon to 90° angle from the hour ring (sometimes also called chapter ring).
4} Orient the magnetic needle North to local declination.

B - Base Plate - Sundials with String (2a) or Blade (2b) Gnomon
1} Place sundial on a flat level surface.
2a} STRING - Erect the cover lid vertically so that the string is pulled tight with no sagging. If applicable, set the string to the relevant latitude of your current location. Select the nearest city indicated on the reverse side.
2b} BLADE - Adjust the blade's scale against the bird's beak according to the latitude of the nearest city indicated at the underside.
3} Orient the magnetic needle North to local declination.
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BIBLIOGRAPHY

- Gatty, Mrs. A. K. "The Book of Sundials." - Edit by H.K.P. Edens & E. Lloyd.  © 1872 - Fourth ed. 1900
- Gouk, P. "The Ivory Sundials of Nuremberg 1500-1700” © 1988
- Higton, H. “Sundials – an Illustrated History of Portable Dials” © 2001
- Lloyd, S.A. ”Ivory Diptych Sundials 1570-1750” © 1992
- Marshall, R.K. “Sundials” © 1963
- Waugh, A.E. “Sundials – Their Theory & Construction” © 1973

Ancient French books dealing with the theory and technique of sundials:
- Traité de la CONSTRUCTION et des principaux usages des INSTRUMENTS de MATHEMATIQUES by Nicolas BION (1709, see below)
- Traité de GNOMONIQUE PRATIQUE by Dom François Bedos de Celles (1709, picture at right),
- Traité de la Construction et des principaux usages des instruments de mathématique (N. BION)
- Traité d'HORLOGIOGRAPHIE de Dom Pierre de Sainte Marie-Madeleine (1701).

Contemporary books addressing more collectors and describing items displayed in Museums and private collections:
- Anciennes INDUSTRIES scientifiques et artistiques DIEPPOISES (55 p.) 1904, by Ambroise MILET, chap. II: Cadrans à boussole.
LES MONTRES SOLAIRES - Booklet of about 30 pages written in 1932 by Commandant VIVIELLE, Head of the French Navy's Library and private collector. This booklet gives valuable information about the different sundial types and the life of the makers.
(Photocopies can be ordered),
- LES INSTRUMENTS DES SCIENCES (Sté fr. du Livre, 1966),
- MESURES DU TEMPS ET DE L'ESPACE (Off. du Livre, Fribourg, 1970).

We reproduced here some pictures of items seen in the older ones and we used some technical definitions and historical facts concerning the items. You will find find more information about this topic (in French and German) on the following website: Gnonomik
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