Berlin instruments of the old Egyptian time of day destination

Herbert Rau, Berlin

It is the great merit of the Egyptologist Ludwig Borchardt to have analysed the theory of time destination from the epoch of the Pharaohs and later on by means of the founds of showpieces and fragments of Old Egyptian water-, sun- and star dials. 1)
A recent discussion of shadow measuring with the help of sundials in Old Egypt 2) and a proposal of Mr. Schwarzinger got the referee to see in the Egyptian Museum of Berlin, in order to do precise documentations about the concerning inventory pieces, respectively to have a look at the card index. 3)

Borchardt differs four methods of the destination of the hours (daytime-) from the position of the sun and one from the position of the stars:

1.1 Measuring of the length of the shadow withhout an instrument by means of a vertically placed yardstick.

1.2 Measuring of the height of the shadow respectively the length of the shadow with the help of an instrument (ruler-sundial with a horizontal plane to catch the shadow).

1.3 Measuring of the length of the shadow with a tool / an instrument (ray of light-sundial with an oblique plane to catch the shadow).

1.4 Measuring of the destination of the shadow direction (vertical south-sundial).

2. Determination of the hours according to the position of the stars.

Precise documentations (all units for measurement are given in mm) and examination of records for the Berlin instruments. .

The photos 4) below show (on a different scale) from the Berlin instruments, respectively from their fragments the inventory number 19743 (picture b), - 19744 (picture b), - 14573 (picture c), - 14084 (picture d), -14085 (picture e), - 22824 (picture f) und -20322 (picture g).
The oldest piece from the Berlin collection might be the ruler-sundial with the inventory number 19744 (photo picture b).

Fotos a - g (20 KB)

Zu 1.1 Measuring of the length of the shadow withhout an instrument by means of a vertically placed yardstick.

Inv. No 7358 , 7th to 4th century B.C.

Inv.No 7358 (3 KB)Implement : Yardstick, former total length about 50cm

Material: Very hard stone

Site of the discovery : ?

Literature : 1) and Roeder in Ägyptische Inschriften II (Egyptian inscription II) 1924, p.310.
In Berlin only the approximately 11 cm long piece does exist, which is broken at both ends.

 

Zu 1.2 Measuring of the height of the shadow respectively the length of the shadow with the help of an instrument (ruler-sundial with a horizontal plane to catch the shadow). 

Inv. No 19744, 1501-1447 B.C. (Thutmosis III.) 

Inv.No 19744 (5 KB) Instrument : Sundial

Material : Green slate

Site of the discovery : Eschmunên ?
Bought by Borchardt from the merchant M.Nahman in Cairo

Literature : Borchardt in ÄZ 48(1910/1911), p.9 to 17.

ÄZ = Zeitschrift für ägyptische Sprache und Altertumskunde
(Magazine for Egyptian language and antiquity-science)

 

 

Inv. No 19743 , 1000-600 B.C

Inv.No 19743 (5 KB) Instrument : Sundial

Material : Green slate

Site of discovery : Fayum ? 

Bought by Borchardt from the merchant M.Nahman in Cairo.

Literature : Borchardt in ÄZ 48 (1910/1911), p.9-17

 

 

Length of the shadow (mm) and altitude of the sun (o) at both instruments Inv. No 19744 and 19743.

Inv. Nr. 19744 und  19743
hour of the day time length of the shadow and altitude of the sun
Inv. No 19744 Inv. No 19743
mm o mm o
12. ∞ 0 ∞ 0
1./11. 162 9 188 9
2./10. 108 13 125 13,5
3./ 9. 66 21 75 22
4./ 8. 32 38 37 39
5./ 7. 11 66 12 68
6. 0 90 0 90
Inv.-No 19743 (3 KB)

Inv. No 14573, 1415 - 1380 B.C. (Amenophis´III.)

Inv. No 14573 (6 KB)Instrument : Fragment of a perpendicular handle; rest of a ruler-sundial; top of a peg or end-block (?)

Material : Wood

Site of the discovery : Bought by Reinhard in 1899

Inscription : Hieroglyphs with the name of Amenophis´III.

Literature : Borchardt in ÄZ 48(1910), p.9 following.

 

 

 

Zu 1.3 Measuring of the length of the shadow with a tool / an instrument (ray of light-sundial with an oblique plane to catch the shadow)

Inv. No 22824  The shadow projecting edge was always lying crosswise towards the azimuth of the sun !

Inv.No 22824 (6 KB) Instrument : Pillar of a sundial. Rau : Top of a peg from a ray of light-sundial with oblique plane to catch the shadow (?)

Material: Black stone

Site of discovery : Bought by Borchardt from the merchant M.Nahman in Cairo.

Literatur: ?

 

 

 

Zu 1.4 Measuring of the destination of the shadow direction (vertical south-sundial).

Inv.No 20322 (5 KB) Inv. Nr. 20322, 4th - 1th century B.C.

Instrument : Roman vertical south-sundial

Material : Blue Faience

Site of the discovery : From Chalid in Luxor

Literature: Borchardt in ÄZ 49 (1911), p.66 following.

Zu 2. Determination of the hours according to the position of the stars .

Inv. Nr. 14085, 6th century B.C. 

Inv.No 14085 (4 KB) Instrument : Perpendicular handle (sundial)

Material : Bone

Site of the discovery : Abydos ?

Hieroglyphs : „I know the course of the sun, the moon and all stars to their site"

Owner : Horoskopen Horus, who was the son of the prince Har-woz and the (Queen) Esetcheb.

Literature : Borchardt in ÄZ 37(1899), p.10 f. and Borchardt in ÄZ 48(1910/1911), p. 9-17

Inv. Nr. 14084 , 6th century B.C.

Inv.No 14084 (3 KB) Instrument: Sight rod

Material: Date palm frond

Site of the discovery : Abydos ?

Literature : Borchardt in ÄZ 37(1899), p.16
Both Instruments together (Inv. No 14084 and -14085) served to take aim at the stars.

Discussion about the Instruments for measuring of the height of the shadow with the help of a horizontal plane to catch the shadow, to 1.2

Borchard proofs, that all time measuring-instruments - also the water clocks - had different sources of errors. He writes in the end 1): „The old Egyptians had just no feeling for accuracy of time determination...“. „They have measured neither equinoctial nor temporal hours.“

To let a shadow fall on the narrow ruler with its hour-marks at these ruler-sundials throughout the whole year, Borchardt puts a yardstick with a five-edge cross-section, crosswise on the top peg. The ruler is lying then in an East-West-direction with the top peg towards east during morning and to west in the afternoon. The yardstick (crossbar) is situated always in North-South-position.

This assembled instrument in a T-shape had to be put into one of the three cross-section-positions, in order to get a reasonable result (p.36 1)).

cross-section-position (4 KB)

The resulting cross-section-positions of the more than 50 cm long yardstick on the relatively narrow top peg of the just as short ruler were certainly unstable, especially the cross-section-position 1.

Borchardt himself writes: „The T-form and also the three positions of the cross-position cannot be proved“ (p.36 1)). Did this T-form of Old-Egyptian sundials exist?

For a simple use of the ruler-sundial, without using the crosswise condition of a yardstick similar to the later one with the oblique plane to catch the shadow, there is much to be said for the following cases :

♦ The complicated change of the cross-wise positions and the instability of the composite implement.

♦ The later sundials with oblique shadow collecting plane also had ray of light.

♦ The concerning characters (hieroglyphs) do not show a T-form.

T-form (1 KB)

♦ The charts of the day-times on the yardsticks (p.27 1)) only show the lengths of the shadow in ells and hand's breadths, the first three and the last three day-times are proved.

The example below shows, that during summer solstice the noon-altitude of the sun came up to the 6th daytime, during equinoctials almost came up the 5th/7th daytime and during winter solstice came up the 4th/8th daytime of the instrument. Were noon-altitudes of the sun for more than 40° no longer acceptable in Old Egypt for daily work, and therefore not so interesting ?
Inv.No 19744 ( 6 KB)

All existing old-Egyptian findigs for measuring the time - at further places - ought to be measured and proofed. The comment of the Egyptolgy is essential.

 

Literature and notes
 1) Borchardt, Ludwig: Die Altägyptische Zeitmessung, Bd.1, Lieferung B, Die Geschichte der Zeitmessung und der Uhren, editor E.v.Bassermann-Jordan, 1920 Berlin and Leipzig.
 2)  Symons, Sarah: Shadow clocks and sloping sundials of the Egyptian New Kingdom and late period : Usage, development and structure, The British Sundial Society Bulletin No 98.3, Oct.1998, p.30-36.
 3)  With permit from Egyptian Museum Berlin, October 1998.
 4) Fotos from Egyptian Museum Berlin: Margarete Büsing, Christiane Olek and Jürgen Liepe

Translation of the German text into English by Reinhold Kriegler / D-28357 Bremen,
e-mail : Reinhold.Kriegler@gmx.de

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Last update : 4. May 2002