British Museum blog

Dotting the ’i’s…

Silke Ackermann, former British Museum curator

It’s been a while since the last post about this project, as much has happened since Josefina wrote about her research trip to Israel. Not least is the fact that I have left the British Museum for a professorship at the University of Applied Sciences at Schwerin (Germany). I will stay involved in the project in various ways, but the British Museum will not.

However, I wanted to write a final post to report on our study of two instruments. One was the famous medieval astrolabe with Hebrew markings in the British Museum, that has already played a role in the BBC Radio 4 series A History of the World in 100 Objects as object no. 62. The other is a later astrolabe in a private collection that had been deposited at the Museum by an owner keen to learn more about his object. This is a service that curatorial departments of the Museum regularly perform.

Josefina Rodríguez Arribas (left) and Silke Ackermann examining an astrolabe

Josefina Rodríguez Arribas (left) and Silke Ackermann examining an astrolabe

We were keen to get a better feel for the instruments; to examine the lettering, and explore the language used to see what it might tell us about the cultural circumstances in which they were made, and to take a close look at a much younger astrolabe, constructed at a time when the instrument had largely gone out of use.

An examination of the markings on both instruments made it quite clear that the language used is Judeo-Arabic in both cases, that is Arabic written in Hebrew letters. This is a phenomenon that can often be observed where Jewish people are living in an Arabic-speaking-community. They may well be speaking Arabic themselves, but will often use Hebrew letters for writing as this is the script they will have learnt. To indicate letters otherwise not used in Hebrew, certain letters will have special signs, normally dots.

Scientific analysis has shown the later piece to be made of rolled metal, a technique that was virtually unknown before the nineteenth century. This means it was made when the use of astrolabes had largely been superseded by other instruments.

When examining this instrument in detail we were struck by the fact that some of the numerals used to indicate values for – amongst other things – latitudes appeared to be full of mistakes. This, together with the late date of the instrument, might on first glance raise suspicion about its authenticity. However, the explanation appears to be a completely different one. One should note that these numerals are not written in ciphers, but in the so-called ‘alphanumerical system’, that is a system used in all Semitic languages (and also in Greek) where each letter of the alphabet also stands for a numerical value. Thus aleph stands for 1, bet for 2 etc. The numbers we had been looking at should have read ‘15’ – jod he in Hebrew. However, this letter combination looks identical to an abbreviation for the name of God – and would thus have been avoided by observant Jews. Other features of this particular instrument seem to indicate that it was carefully copied from an earlier source, probably by a scholar who was reading the medieval texts trying to understand or to teach how such an instrument might have worked.

I know I’m biased, but isn’t it truly amazing what we can learn just by looking at instruments?! Working in a museum one soon begins to realize that it is often objects that give us the cultural and social contexts that we cannot glean from written sources alone – and it is the combination of instruments and texts as the historical basis for our research that makes this project so exciting for me.

For more information about this project, visit the Warburg Institute website

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You can now discover thousands of British Museum objects in partnership with @googleartproject at We’ve asked staff members to highlight their favourites and explain what makes them special. Chris Spring, Curator of Africa Collections, describes why he finds the ‘Throne of weapons’ so powerful. ‘This war memorial celebrates the ordinary people of Mozambique, many of them unarmed, who stood up to a culture of violence. It represents both a human tragedy and a human triumph. The Throne's essential humanity is suggested right away by its anthropomorphic qualities - it has arms, legs, a back and most importantly a face - actually two faces. My first reaction was that these faces are crying in pain, though they could also be seen as smiling faces finally freed from conflict. These anthropomorphic qualities also link it immediately to the arts of Africa, in which non-figurative objects such as chairs, stools, weapons, pots etc are seen as - and described as - human beings. The Throne has toured the world, taking its message of peace to schools, churches, shopping centres and even prisons – and of course, to museums and galleries.’ #MuseumOfTheWorld We’re celebrating our partnership with @googleartproject, and have asked curators to tell us about their favourite objects. Hugo Chapman, Keeper of Prints and Drawings, explains why he chose this chalk drawing by Michelangelo. ‘One of the things I love about drawings is the way they sometimes allow a glimpse into the private, behind the scenes world of an artist, one unseen in finished works in paint or stone. An example of that is a red chalk drawing by Michelangelo of grotesque heads in red chalk that reveal that the Florentine Renaissance artist had a lively, if caustic, sense of humour. The three heads were probably drawn to amuse but at the same instruct his pupils, as the three studies show how slight changes can radically alter the reading of an image with the character and mood of each figure (paranoid anxiety; vacuous joy; and depressive gloom) signalled by the position and erectness of their donkey-like ears.  I wish my ears were as expressive.’ Discover many more incredible works of art in the Google Cultural Institute at

#Michelangelo #art To celebrate our partnership with @googleartproject, we’ve asked members of British Museum staff to highlight their favourite objects and explain what makes them special. Jill Cook, Deputy Keeper of Britain, Europe & Prehistory, chose this stone chopping tool from an early human campsite in Olduvai Gorge, Tanzania. ‘Holding this 2 million year old African tool in my hand I am reminded that whatever differences exist between people now, we are united by our common origin in Africa. The discovery of this piece by Louis Leakey in 1931 began to change our understanding of what makes us human. It illustrates the beginning of a transition from an ancestral ape that walked upright on two legs within the confines of a limited ecological niche to humans with more complex brains capable of changing and eventually dominating the world around us by making tools and weapons. This chopping tool is one of the seeds from which all human cultures and societies have grown.’ Discover the stories of thousands of objects in the Google Cultural Institute at

#MuseumOfTheWorld In Victorian England many people were fascinated by their past, and the ancient tribal leader Caratacus (also spelt Caractacus) was adopted as a symbol of national pride and independence. Like Boudica, Caratacus resisted the Roman invasion of Britain. Although he was eventually defeated, he earned a reputation as a noble and worthy foe. The Victorian sculptor J H Foley portrays him here standing triumphant, the embodiment of courageous English spirit. See this incredible #Movember moustache in our #Celts exhibition, until 31 January 2016.
J H Foley (1818–1874), Caractacus. Marble, 1856–1859. On loan from Guildhall Art Gallery/Mansion House, City of London. Some more #Movember inspiration! Here’s the Museum’s security team from 1902 photographed on the front steps. They include officers from the Metropolitan Police, and the London Fire Brigade (identified by their flat caps). We’re celebrating #Movember with Museum moustaches great and small. Here’s a #Movember fact: Peter the Great of Russia introduced a beard tax in 1698 and this token was given as proof of payment!

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