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DescriptionsandImagesoftheEarlyMedievalLatinAbacus
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oftheabacus(andinadeparturefrom[V],thesiliquaisstatedherecorrectly,as
wellasitsmultiples,thebissiliquaandthetremissis).
Plate8.TheOxfordabacus[J](aroundyear1110);drawingacc.toOxford,St.John’sCollege,
MS17,48v149r
Thereisanotherschemaforacomputingtoolintheverysamemanuscript
(Oxford,St.John’sCollege,MS17,f.35r),calledAbbonisabacus,and,since
AbboofFleury,knownastheabacidoctor
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,wasthecontemporaryoftheold-
estLatinpre-scholasticorearlyscholasticabacists,wecannotleaveoutthis
so-calledAbboabacuseither(seeplate9)
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.However,abriefglanceatthis
drawingsoonrevealsthatitisnotarealabacusatall.Twotriadsofcolumns
areroofedbyarchesinthe“abacistic”manner,andthecolumnsappearto
representdecimalscales(fromunitstohundredsofthousands),afactwhich
isalsoreflectedbytheinscribedheading,whichconveystheinformationthat
numbersupto999,999canbeexpressed
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.However,atthispoint,allsimilari-
tieswithanabacusend.Theunitsareplacedontheleft(notontheright),the
individualcolumnscontain(forthenumberswrittenincorrectlyfromleftto
right)numericvaluesforeachparticularscale(forunits119,fortens10199
etc.),sothattheentiretableremindsusmoreofamerelistofquantityvalues
ratherthananabacus.Othertypicalfeaturesarealsomissing1units,hun-
dreds,andthousandsfortriadofcolumns,informationonthewestern-Arabic
numerals,fractions,andsoon.Itisobviousthat,inthiscase,itisnotan
abacistictool.
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OneofthepreservedmanuscriptsofAbbo’scommentariesontheVictorius’stextis
concludedinthismanner1seeAbboofFleuryandRamsey:Commentary…,p.xxxviii;
seealsoAbboFloriacensis:Excerpta…,p.203.
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Foritsanalysis,incl.photocopyseeCh.Burnett:AbbondeFleuryabacidoctor.In:
AbbondeFleury.Philosophie,sciencesetcomputautourdel’anmil.Ed.B.Obrist.Paris
2006,pp.1291139(“Oriens-Occidens.Sciences,mathématiquesetphilosophiedel’Antiquité
àl’Ageclassique”,no6),resp.p.211;fordigitalcopyseeonline:http://digital.library.mcgill.ca/
ms-17/folio.php?p=35r.
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SeeAbbonisAbacus…,p.203:“Inhacfiguradescriptusestnumerusinfinitus:incipit
enimabunopervenitqueusqueadnongentesimummillesimum”.Seealsoonline:http://digital.
library.mcgill.ca/ms-17/folio.php?p=35r.
