Determination of the Centre of Construction, Anonymous Single-manual Harpsichord, sold by me to the Markiezenhof Museum, Bergen op Zoom, The Netherlands


Anonymous single-manual harpsichord, Naples, c.1620

Property of the Markiezenhof Museum, Bergen op Zoom, The Netherlands

The case, lid and stand are all of modern construction


           The city or region of construction of an anonymous instrument can be determined by analysing the size of the unit of measurement used in its construction.  Until the time of the Napoleonic invasions of the Italian peninsula each of the major centres in Italy used its own unit of measurement, and the size of these units varied from place to place.  The braccio, piede, canna, palmo, etc. and their subdivision into the oncia, soldo or pollice were therefore characteristic of each of the centres in which instruments and virtually all other manufactured items were built.  Therefore if the unit of measurement used in the design and construction of an instrument can be determined, this can be used in turn to establish the centre of its origin.  This is a fundamental procedure, basic to the process of establishing the region in which an instrument originated, and can be a great help in establishing the maker of an otherwise anonymous instrument.

           It is quite clear that any maker of instruments - or any other object for that matter - would have worked on a day-to-day basis using convenient numbers and uncomplicated fractions of his local unit of measurement.  For the plain reason that whole numbers or simple fractions are easy to remember, an artisan would work in convenient units of measurement when he is designing and executing the object he is making.  Because most of the measurements used are, to a certain extent at least, arbitrary there is no need to invoke complicated numbers in their design.  This is clear to anyone who has lived or worked anywhere in much of the English-speaking world where the inch, a twelfth part of a foot, was until recently still being used.  Most of the measurements used by hand-workers, artisans, artists, architects, designers and all of those involved in industry and commerce were based on simple numbers of inches, feet, and yards, or on their simple subdivision.

           Only where it is really necessary and where dictated by some rule or theoretical concept would an instrument builder use a complicated or irrational division of the local unit of measurement.  This has been shown clearly from the ground-breaking study made of many types of musical instruments by Herbert Heyde[1].  Further work that I have done recently in this field shows that the maker began his design by drawing out the baseboard using dimensions which were simple integers or fractions of the local unit of measurement, and the case sides that he then applied to the outer edges of the baseboard were cut to a height also equal to a simple number of units (or units plus simple fractions) of the local measurement unit.  It is normally the height of the case without the top cap moulding in Italian instruments, and without the added thickness of the baseboard in North-European instruments, that the maker would measure in his local unit of measurement[2].  He would mark out a number of planks all in convenient units and all of the same width, and then cut and apply these to the outside edge of the baseboard.  Experience has shown that even here the case-wall heights are often slightly less than expected in places where the top of the case has been planed down to equalise the level of the top edges at the corners when these did not match exactly after the case sides were assembled.  It is therefore the maximum case-wall height that corresponds to the makers design and not the average case-wall height.  Similarly the position and measurements of all of the other design features of the instrument were made by choosing simple units of the local unit of measurement.  Clearly which measurements were chosen by a maker in simple units would depend on his method of working and especially on the order in which the various operations necessary to construct the instrument were carried out.

           The problem faced by an investigator is to find the unit of measurement used to design and construct any given instrument.  An instrument has many different measurements and it is not at all obvious from looking at these expressed in millimetres what the local unit used to arrive at them was.  Even knowing that the baseboard was constructed using simple units of the local measurement is not, in itself, enough to divine the length of the unit used in its design.  This is further complicated by the fact that, being hand made, none of the measurements of the baseboard or the rest of the case, keyboards, string-length scalings, etc. is perfectly exact.  Any method used to find the unit of measurement must therefore also be relatively insensitive to any inaccuracies resulting from the working methods of the maker.

           The method used by these makers is based on the way in which they used a simple geometrical construction to arrive at the tail angle of harpsichords[3].  Working in reverse, a study of the measurement of the angle and of the orthogonal components of the tail side enables a calculation of the unit of measurement.  Establishing the unit of measurement used in the design of the instrument can then be used to determine the centre in which it was built. 

           The importance of such a method to the determination of the maker of an anonymous instrument is obvious.  The method clearly does not pinpoint precisely who the maker was, but it does reduce the number of possible makers from the vast breadth of builders active across the whole of Italy.  The following analysis uses this method to determine where this otherwise anonymous harpsichord was originally built.

           In order to determine the unit of measurement used to measure this instrument the baseboard was measured (not including the case sides) and the position of various lines scribed on the baseboard were also measured.  These are shown in Table 1 below.

Length:     1989
Width:     747 at front; 742 at the bellyrail
Cheek:     478
Tail:     196½
Component of the tail parallel to the spine:     67
Component of the tail perpendicular to the spine:     186
Tail angle:     70½º
Depth of keywell:     125
Width of wrestplank in the treble:     148
Width of wrestplank in the bass:     188
Width of gap:     44
Width of belly rail:     26
 Width of upper belly rail:     17½

Table 1 - Original dimensions measured out on the baseboard.

Anonymous single-manual harpsichord, Naples, c.1620

Property of the Markiezenhof Museum, Bergen op Zoom, The Netherlands


          The procedure of determining the unit of measurement used to construct this harpsichord begins most easily with the measurement of the angle of the tail.  The tangent of this angle is .  This suggests that the two sides of the triangle that form the tail angle are 8½ once and 3 once.  The measured lengths of these two sides in mm divided in turn by these numbers gives an approximate estimate of the size of the oncia which can then be applied to the other measurements of the baseboard, keyboard, wrestplank, string scalings, and all of the other parts and design features of the instrument.  These sides have lengths of 186mm and 67mm and their ratio gives:

This, in turn, suggests that the length of the unit of measurement used in the construction of this instrument is about mm or mm, and these can be used to give an initial estimate of the unit of measurement in order to calculate the other dimensions in the same units.

           A summary of the measurements of the baseboard, the scribed lines on it, and the case height millimetres and in once are given in Table 2 below.



Length of
in mm unit oncia
Component of tail perpendicular to spine: 186 = once gives 21.88mm
Component of tail parallel to spine: 67 = 3 once gives 22.33mm
Long side: 1989 = 90½ once gives 21.98mm
Baseboard width: 747 = 34 once gives 21.97mm
Baseboard cheek (short side): 478 = 21¾ once gives 21.98mm
Width of wrestplank in bass: 188 = once gives  22.12mm
Width of wrestplank in treble: 148 = once gives 21.93mm
Depth of keywell: 125 = 5.7 once gives 21.93mm
Width of gap: 44 = 2 once gives 22.00mm
 Thickness of bellyrail: 26 = 1.2 once gives 21.67mm
Thickness of upper bellyrail: 17½ = 0.8 once gives 21.88mm
Case sides height:    190 =  once gives 22.35mm
Totals 4205½ = 191.2 once Average: 21.995mm

Table 2 - Calculation of the unit of measured used to design and construct this instrument.

Anonymous single-manual harpsichord, Naples, c.1620

Property of the Markiezenhof Museum, Bergen op Zoom, The Netherlands


          This length, 21.995mm, can be compared with a number of similar units of measurement used in the Italian peninsula in Table 3 below (see also A list of Italian units of measurement arranged according to the length of the unit).  Clearly the centre which used a unit closest to that found here is Naples where, in addition to the oncia of 21.835mm, an oncia of length 21.973mm was used.  This must correspond to the unit that was used in the construction of this instrument[4].  The instrument has many features of other instruments made in Naples as discussed below.  Although Genoa also used a unit near to that found here the fact that no seventeenth-century harpsichord makers are known to have worked there and the similarity of the instrument to those made in the Neapolitan tradition excludes Genoa as the centre in which this instrument was made.  No other centre had a unit of measurement as close in value to that found for this instrument.  The error between the value found here and the value given in the tables of metrology is only 0.1%!


          This therefore suggests that Naples is the centre in which this harpsichord was built.



                                      Large                 Length                         Sub-        Length                    Reference

    Location                   Unit                   in mm      Division     unit         in mm                       source*

      Genoa                    Palmo                  248.08            12           oncia         20.674    Ca,Did,GDE,Mal,Mar,Kr,Cha

       Rome            Palmo mercantile          248.99            12           oncia         20.749         Eu,Mar,Mal,Dou,Pa,Co

Sicily/Palermo            Palmo                   257.80            12           oncia         21.483                    Mal,Eu,Mar

      Naples                  Braccio                  698.00            32           oncia         21.813                            Ca

      Naples                   Canna                 2096.10           96           oncia         21.834              Ca,Dou,Pa,Or,Cha

      Naples                   Palmo                  262.01            12           oncia         21.835                        Dou,Cr

    Naples                  Canna                  2109.36          96           oncia         21.973                    Ga,Mal,Mar

    Naples                  Palmo                   263.67           12           oncia         21.973                Did,Ga,Mal,Mar

      Genoa                     Piede                   263.93            12           oncia         21.994                           Did

      Savoia                   Braccio                  270.70            12           oncia         22.558                            Kr

     Verona                    Piede                    270.90            12           oncia         22.575                            Co

Table 3 - Some units of measurement used in the Italian peninsula in the historical period[5]


*The abbreviations used in the table above refer to the following:

Ca          Hercule Cavalli, Tableaux comparatifs des mesures, poids et monnaies modernes et anciens…, (Paul Dupont, Paris, 2/1874).

Cha        Chambers, Ephraim, ‘Measures’, Ciclopædia:  or An Universal Dictionary of Arts and Sciences, Vol. 2 (London, 1728; 4/1741; 5/1743).

Co          Colonel Cotty,  Aide-mémoire a l’usage des officiers d’artillerie de France, 2 (Paris, 1819) 896-7.

Cr           Giovanni Croci, Dizionario universale dei pesi e delle misure in uso presso gli antichi e moderni con ragguaglio ai pesi e misure del sistema metrico, (The Author, Milan, 1860).

Did        Denis Diderot and Jean Henri le Rond d'Alembert, ‘Pied’, Encyclopédie ou dictionnaire raisonnée des arts, sciences et métiers, 7 (Paris, 1751-65) 562-563.  Diderot gives his measurements as 1440-th parts of the Paris pouce, and Colonel Cotty’s military manual was used for the length of the pouce.

Dou       Horace Doursther, Dictionnaire universel des poids et mesures anciens et modernes, (M Hayer, Brussels, 1840).

Eu          Ludovico Eusebio, Compendio di Metrologia Universale e Vocabolario Metrologico, (Unione Tipografico Editrice Torinese, Turin, 1899; reprint by Forni Editore, Bologna, 1967).

Ga          Giovanni Gandolfo, Tavole di ragguaglio ovvero prontuario di computi fatti di pesi, misure e monete legali italiane, (Naples, 1860).

GDE      Anon., ‘Misure’, Grande dizionario enciclopedico,  12 (Unione Tipografico-Editrice Torinese, Turin, 1970) 626.

Kr           Johann Georg Krünitz, Öconomische Encyklopädie oder allgemeines System der Staats-, Stadt-, und Landwirtschaft, in alphabetischer Ordnung, 15 (Jospeh Georg Traßler, Brünn, 1788) 519-22.  Given as 1440-th parts of the Paris pouce; Co used for pouce.  See Did.

Mal        L. Malvasi, La metrologia italiana ne' suoi cambievoli rapporti desunti dal confronto col sistema metrico-decimale, (Fratelli Malvasi, Modena, 1842-44).

Mar        Angelo Martini, Manuale di metrologia, (E. Loescher, Turin, 1883; reprint Editrice Edizioni Romane d’Arte, Rome, 1976).

Or           Barnaba Oriani, Istruzione su le misure e su i pesi che si usano nella Repubblica Cisalpina, (Milano, 1891).

Pa           Luigi Pancaldi, Raccolta  ridotta a dizionario di varie misure antiche e moderne coi loro rapporti alle misure metriche…, (Sassi, Bologna, 1847).


          Figure 2 below shows the measurements of the baseboard and of some of the scribed lines on the baseboard measured in millimetres on the left and in units of the Neapolitan oncia as determined above.



Figure 1 - The scribed lines and dimensions of the baseboard in millimetres (on the left)

and in nominal units of the Neapolitan oncia = 21.995mm (on the right).

Anonymous single-manual harpsichord, Naples, c.1620

Property of the Markiezenhof Museum, Bergen op Zoom, The Netherlands




[1] See:  Herbert Heyde, Musikinstrumentenbau, 15.-19. Jahrhundert.  Kunst Handwerk Entwurf, (VEB Deutscher Verlag für Musik, Leipzig, 1986).

[2] In the North-European tradition where the case sides are much thicker than in Italian practice, the top moulding is often cut into the wood of the case side itself, and the case sides are usually (but not always) applied to the top of the baseboard.  In Italian instruments it is therefore the case height less the thickness of the top cap moulding that the maker would measure out using a simple number of local units; for North-European instruments it is the case height less the thickness of the baseboard onto which the case sides are placed.

[3] See my article ‘The use of simple geometry and the local unit of measurement in the design of Italian stringed keyboard instruments:  an aid to attribution and to organological analysis’, The Galpin Society Journal, 52 (1999) 108-171 which is also given here at Geometry and the Unit of Measurement.

[4] There was a decimal division of the oncia in Naples.  Often a fifth of an oncia called a minuto was used.  But clearly halves and quarters of the oncia was also used as well as the division into tenths.

[5] See my article quoted in footnote 3 and the database of the Italian units of measurement  in Table 11 with further information in Appendix 2.


- Grant O’Brien                    

- Edinburgh, October, 2000


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