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


Grant O'Brien


Appendix 2 - Italian Metrology c.1500 to 1800


          An excursion into the field of historical Italian metrology is not for the faint hearted!  It is a Pandora’s box full of unexpected tricks waiting for the unwary.  As the whole of the Italian peninsula gradually changed to the metric system during the nineteenth century, numerous works were published dealing with the conversion of the units of measurement of length, area, volume and currency into the new metric system which had been imposed by law first of all after the Napoleonic invasions of the North, and eventually after the Unification of Italy as a whole.  The measurements given by the authors of these works are, however, not always the ones which were actually used in the Italian peninsula in the historical period of harpsichord building.  In some areas the standards were changed in the period after that in which harpsichords were built but before the publication of the works on metrology.  In Florence, for example, the unit of length was increased by a factor of 17/16 (6¼%) as a result of legislation passed on 2 July, 1782, and also an increase of only 0.1% in Piemonte in 1818, and by 0.333% in Naples after 1841.  It is therefore necessary to be sure that one is, in fact, applying the correct unit of measurement to an instrument in assigning to it its putative place of origin.

          The other problem faced by a worker in this field is that there were various subdivisions of the palmo, piede and braccio.  These were variously into 10, 12, 16, 20, etc. units and so it is clearly essential to understand how each of the units, whether the palmo, piede, braccio, oncia, pollice, etc., were subdivided.  Although these were usually into 12 units, a division into 10 units was common in many of the towns in the Province of Emilia-Romagna.  The latter division is not to be confused with the decimalization of the larger units introduced in some parts of Italy, for example in Sicily, during the nineteenth century.  The division of the braccio was usually into 20 units, but divisions into 12, 16, 22, etc. were also known.  When used for measuring cloth, the braccio was often divided in halves, quarters, eighths and sixteenths.  The sub-division of the units of measurement used in the design of early keyboards instruments and found a number of important centres is given below and in tables 11 and 12 at the end of this Appendix.


Cagliari and Sardinia:

1 canna = 10 palmi; 1 piede = 2 palmi = 12 once; 1 palmo = 6 once; 1 oncia = 12 punti (Dou, Eu).


          A law was passed in Florence on 2 July, 1782 which changed the length standard in Tuscany, as noted above, so that the value of the soldo = 29.18mm used from then until 1 July, 1861 is not valid for the historical period.  In Florence and much of Tuscany 1 braccio = 2 palmi = 20 soldi = 12 crazie = 60 quattrini = 240 denari, so 1 palmo = 6 crazie = 10 soldi = 30 quattrini = 120 denari, and 1 soldo = 3 quattrini = 12 denari and 1 crazia =  soldi = 5 quattrini = 20 denari and 1 quattrino = 4 denari.


1 braccio = 12 once = 144 punti = 1728 atomi = 20736 momenti (Cr, page 38).


          A law was passed on 6 April, 1840 which increased the length of the palmo and other units of measurement in Naples and the surrounding area which came under the influence of the Kingdom of Naples by about 0.3338%, a small amount (see Ga, 1864).  Any sources such as Mal 1875 give the later value of the length without taking into consideration the value before 1840.  In Naples 1 canna = 8 palmi = 96 once = 480 minuti, so 1 palmo = 12 once = 60 minuti = 600 punti, and 1 oncia = 5 minuti = 50 punti, hence the oncia is divided in 5 parts and not in 12!


1 piede da legno = 12 once = 144 punti = 1728 atomi = 20736 minuti = 248,832 momenti = 2,985,985 scrupoli (Source:  Cr page 39).

Piemonte (especially Turin, but valid throughout all of the smaller and larger centres in Piemonte):

14 once = 1 raso (braccio da panno); 8 once = 1 piede manuale.  According to Mar, p.783, Eu, p. 46 and others, the value of the piede was changed from 513.766mm to 514.403mm in 1818.  Before 1818 (except for the period in which Napoleon dominated Savoy from 1798 to 1816 and therefore outwith the historical period of stringed keyboard instrument making) all of the other measurements were based on the piede legale, piede liprando or the raso with an oncia = 42.814mm.


          There were three, probably four, basic sizes for the oncia in Rome.  One, equal to about 18.617mm, was used for almost all of the normal measurements of objects, buildings, wood, etc. and was the basis of the palmo romano, piede romano, braccio romano, passetto, passo, and canna architettonica.  Cloth appears to have been measured in units of two different once, equal to about 17.67mm and 20.75mm, and were the basis of the palmo mercantile, palmo da tela, braccio mercantile, braccio da tela, braccio da tessitore, canna mercantile, etc.  The piede (close to 297.9mm) was normally divided into 16 units of the 18.617mm oncia, but it also appears that it was divided into 12 once giving another oncia of length near 24.82mm (used, for example, by Francesco Fabbri and Giambattista Boni both of whom worked in Rome).  Dou says that the piede antico = 294.5mm was still in use in 1840.  In Rome 1 piede =  palmi = 16 once.  1 palmo = 12 once.  1 oncia = 5 minuti = 10 decimi, hence the oncia is divided in 5 or 10 parts but not in 12!


          Tables 11 and 12 give the sizes of the units of measurement current in all of the centres in which harpsichord and virginal makers were active in the historical period, as well as a few additional centres which were important culturally and commercially.  These are arranged both according to the centre and according to the size of the oncia, soldo or pollice.  Also listed on this site for downloading are the complete databases from which these two tables were extracted.  The tables below are the condensation of the larger database which has about 2,500 entries and do not include any measurements given by the nineteenth-century sources for the period outwith the historical era of harpsichord building.  Sources such as Co, Did, Cha and Kr which were actually published in the historical period are often listed separately in the tables below because of their obvious importance and, usually, accuracy.

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