Egyptian Cubit Rods and Cubits

 

Part I -- Introduction and Survey

 

Dieter Arnold, Building In Egypt, Pharaonic Stone Masonry, Oxford University Press, 1991, page 251, remarked on our knowledge of Egyptian cubit rods:

 

 

In order to more thoroughly understand available evidence I survey their work and other published results on cubit rods.  My sources include:

 

1. The Ancient Egyptian Cubit and Its Subdivisions, Richard Lepsius, first published in 1865, now in English translation, with Michael St. John as editor, Museum Book Shop, London, 2000.

2. Ancient Weights and Measures, Flinders Petrie, Aris and Phillips, Ltd., Warminster, England, 1926, pages 38 to 41.

3. Three Cubits Compared, Michael St. John, Museum Book Shop, London, 2000.

4. Metrological Examination of Some Cubits Preserved in the Egyptian Museum of Turin, Dino Senigalliesi, La Rivista RIV, Turin, 1961.

 

I am indebted to Michael St. John for supplying me with a copy of the Senigalliesi report.

 

I also consulted two publications of Von Adelheid Schwab-Schlott, Altagyptische Texte uber die Ausmasse Agyptens, Deutschen Archaologischen Instituts, Band 28, Kairo, 1972 and Die Ausmasse Agyptens nach Altagyptischen Texte, Harrassowitz, Wiesbaden, 1981.

 

In his 1972 report his first example is from the Turin Museum, Supplement #2681, an ornamental fragment, not measured by Senigalliesi. The remaining four fragments are from the Cairo Museum.

 

In his 1981 report he shows the inscriptions on 19 ornamental fragments, drawings or photographs of nine others, and one rod nearly complete.

 

All items were all highly decorated ornamental pieces with insufficient evidence published by Schwab-Schlott to estimate practical measuring scales. The pieces were not adequate to evaluate actual use as cubit rods.

 

In addition Petrie published two other items. See Kahun, Gurob and Hawara, London, 1890, page 27, and

Il-lahun, Kahun and Gurob, 1883-1890, London, 1891, page 14. These included drawings and pictures but were only on small pieces not suitable to this analysis.

 

Lepsius published drawings of his first nine examples, and of two rods then in Leiden, made from paper squeezes. These are not adequate to precise metrological analysis; hence I make no attempt to measure from his drawings. He made some mistakes to further cast doubt on the values. I show his published total rod lengths in later discussion.

 

From the survey I conclude that extant evidence is insufficient to properly assess the history of cubit measurements in ancient Egypt. All available examples are from later periods and, among them, show degradation from rigorous standards. However, the evidence is informative about measurement practices in the periods post 1500 BC.

 

The Turin Museum Rods

 

The measurements by Dino Senigalliesi included five rods. These were:

 

Specimen #1: Museum Supplement # 8391. Folding wood rod from the funerary chamber of the architect Kha, found in its original leather case. No hieroglyphic dedication. A typical cross-sectional shape of five surfaces with a bevel face. One scale inscribed on three sides B top, bevel face, and front. This was truly a working-man=s rule.

 

My thanks to Marcella Trapani of the Turin Museum for the information about the leather case.

 

Note that this rule had no hieroglyphic dedication. This is informative on the difference between a practical rod, and those rods that carried religious symbolism. Kha apparently felt no need for religious dedication for an instrument he used in his daily activities. This raises the question if all rods with religious symbolism were merely ornamental rods, or if this was a personal preference. We would expect that someone in Kha=s social position would use religious symbolism if it were symbolically important to his administrative function. If rods decorated with religious symbols were purely ornamental then their popular appeal among Egyptologists may have had an undue influence upon our understanding. See following discussions.

 

Specimen #2: Museum Supplement #8647. An ornamental wood rod overlaid with gold from the funerary chamber of Kha and presented to him by Amenhotep II, in honor of his work. It is decorated with dedication hieroglyphs on the two ends and on four surfaces, including the bevel face, the top, back, and bottom. The single scale is on the front surface. This rod is in sharp contrast with undecorated Specimen #1, both from Kha, and both found in his funerary chamber. The contrast provides some insight into the differences between daily life and religious observations.

 

Both these rods date to circa 1400 BC and the New Kingdom.

 

Specimen #3: Museum Catalog #6347. (In)famous ornamental wood rod of Amenemope (Amenemipt) from Saqqara, (Memphis according to Lepsius), 19^th Dynasty, circa 1300 BC. This example greatly influenced Lepsius in his attempt to devise a typical cubit rod. It is decorated with dedication hieroglyphs on the back, top, and bevel face. Scales of different divisions are on the top, bevel face, and front. This rod was compared with two rods from the Louvre by St. John because of their similarities in general shape, hieroglyphic inscriptions, scales, and placement of scales. (Paris 1 is the Maya cubit rod.)

 

Specimen #4: Museum Catalog #6349. Square bronze rod inscribed on one side with hieroglyphs. The other three sides have each different scales. The provenance of this rod is uncertain but apparently came from Thebes. This rod may be an example where limited hieroglyphic inscriptions were included yet designed as a practical measuring device. Based on the disagreement among scales and the nature of the hieroglyphs Lepsius classified this rod as a fake. However, analysis of the scales shows its practical usefulness.

 

Specimen #5: Museum Catalog #6348. Basalt rod of green-black color inscribed with hieroglyphs on the bottom. The back has no inscription. A slightly sloping top and the bevel face have coarse scales. The front has the working scale. The provenance is uncertain.

 

The last three Turin rods were first discussed in detail by Richard Lepsius in 1865: the wooden Amenemipt rod (Lepsius #1, Plate 1b, Senigalliesi specimen #3), the green-black basalt rod (Lepsius #7, Plate 4a, Senigalliesi specimen #5), and the bronze rod (Lepsius #8, Plate 4b, Senigalliesi specimen #4).

 

The attempt by Lepsius to derive a standard rod from the New Kingdom ornamental rods greatly influenced generations of Egyptologists, perhaps to the detriment of solid understanding of Egyptian measurement methods. Some of his assignments of hieroglyphs, rod divisions, and assumptions of purpose were speculative and further detracted from practical understanding. As he stated:

 

AYet it cannot be doubted that the ancients were able to make accurate measurements and possessed precise yardsticks, which could not be changed arbitrarily; it is curious that not a single one of these has yet been discovered . The question now is whether the subdivisions in the preserved specimens allow us to reconstitute this exact standard.@

 

This assessment has not been seriously altered in the past 150 years. We are still uncertain of the design of practical working rods. Further, the differences in length of extant rods from these later historical periods shows that rigorous standards had been lost. The evidence speaks to manufacture of rods that seemingly were arbitrary in their lengths, as though produced by guesswork. In other words, Royal Administrations no longer had control of measurement Standards. In contrast, evidence from the Old Kingdom structures speaks to rigorous standards at that time.

 

The concern of Lepsius was further expressed in his struggle to find a reason for division of the standard cubit into 7 parts, and why there were Agreat@ and Asmall@ cubits. He asked:

 

AIt is also obvious how improbable it would be that one would have used a shorter cubit alongside the Aroyal one,@ at the same time and in the same place, the difference between these construction cubits being the width of a palm . . .

 

AWhence the unnatural and impractical partition, (into 7 parts), which allows for only one integral subdivision of the cubit without fractions of a palm? . . . The assumption that the great or royal cubit, not just the small one, would have been divided into only six palms seems so much more probable to me.@

 

An attempt to show evolution of cubit rods is hampered by the great differences among extant examples, lack of examples from early Egyptian history or the predynastic period, and lack of long-term continuity that we can reliably follow. My emphasis here is on the conceptual logic behind the cubit design; therefore, I shall not enter into a review of Lepsius, who concentrated on ornamental rods, and discussed so often before. The contrast between the working rod of Kha and the ornamental rods is a dramatic illustration of how confused our understanding has been. The comparisons of Michael St. John were limited to ornamental rods and do not reflect practical instruments. The prominent position of the ornamental rods may be due to their exciting nature and consequent preservation, while working rods were mundane without attributes of note, and hence not preserved. We today might quickly forget an ordinary tape measure while a gold pocket watch would garner much care.

 

Senigalliesi made refined measurement on a machine bed capable of resolution to thousands of a millimeter but he did not publish the individual positions of the inscribed marks on the respective rods. He published only mean values of intervals, differences between the longest and shortest intervals, standard deviations of the differences, and overall lengths. This method prevents a rigorous metrological analysis such as that available from Petrie=s meticulous method of recording the actual positions of all inscribed lines. For example, it prevents us from determining the accuracy and perpendicularity of the lines. (The thickness of inscribed lines is greater than a half-millimeter. Where did Senigalliesi set his optical equipment?) He would have been of more benefit had he published the exact details and then included a separate mathematical treatment of the results.

 

I convert metric dimensions to English inches in order to maintain a standard unit of comparison, with the conversion of 25.4 mm per inch. My reason is the unusual relationship to English dimensions I shall discuss later. Unless otherwise noted the dimensions are in English inches.