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

A virginal dated 1641 by
Stefano Bolcioni, Florence, in the
Musikinstrumentenmuseum, University of
Leipzig

The virginal
by Bolcioni in the Musikinstrumentenmuseum at the University of Leipzig[39] is in a fairly ruinous state, but
very interesting as a result of never having been restored in modern times[40]. This instrument is signed ‘Stefanus
bolcionius Pratensis 1641’ written in cursive script in ink on the back of the
namebatten[41].
The compass is C/E to f^{ 3} with a broken short octave with
split D/F^{#},
E/G^{#}, and then
split g^{#}/a* ^{b}* and g

It is a rectangular virginal with the right rear corner missing from the rectangle so that, placed in its outer case, the empty space provides a toolbox in the normal way. Here the only triangle which can be used to make an initial estimate of the unit of measurement is that of this rear toolbox space. A summary of the original measurements of the baseboard and case height is given in Table 9.

**
** **Measured**

**
dimension**

**
mm**

Length: 1592

Length of rear spine: 1244

Baseboard width: 424

Short right-hand end: 136

Case left of the keywell: 384

Keywell: 710

Case right of the keywell: 498

Keywell projects: 117

Component of toolbox side along the spine: 348

Component of toolbox side along the right side: 287

Angle of toolbox side: 50½º

Height of case sides: 210

tan 50½º = 1.213
≈
1.214 = _{} _{} = 1.2125

**Baseboard dimensions and case height**

**
Rectangular virginal by Stefano Bolcioni,
Florence, 1641**

**Musikinstrumentenmuseum, University of Leipzig**

**
(On loan from the
Leipzig Museum für Kunsthandwerk)**

**
Analysis of the unit of
measurement used in the construction of the Leipzig Bolcioni rectangular
virginal:**

The procedure
for determining the local unit used to construct this virginal begins with the
measurement of the toolbox angle at the rear right-hand corner of the
instrument. The tangent of this angle
is tan 50½º = 1.213 ≈
1.214 = _{} and this suggests
that the two sides of the triangle that form the toolbox are 12¾ *soldi* and 10½ *soldi* which, mathematically, would form an angle of 50.53º. This angle is very close to the measured
angle of 50½º. Measurement in
millimetres of the length of the two orthogonal components of the toolbox side
gives an approximate estimate of the size of the *soldo*. Table 10
shows the calculation of the unit of measurement used in the Bolcioni
rectangular virginal based on the assumption that the sides of the toolbox at
the rear right-hand side of the instrument were constructed geometrically using
lengths of 12¾ *soldi* and 10½ *soldi*.

**
Measurement Local Length of**

**
in mm unit soldo**

Toolbox
angle component parallel to spine: 348 = 12¾ *soldi*
» 27.29

Toolbox angle
component perpendicular to spine: 287 = 10½ *soldi*
» 27.33

Total
length: 1592 = 58¼ *soldi*
» 27.33

Length of rear
spine: 1244 = 45½ *soldi*
» 27.34

Baseboard
width: 424 = 15½ *soldi *
» 27.35

Short right-hand
end: 136 = 5 *soldi*
» 27.0

Case left of the
keywell: 384 = 14 *soldi *
» 27.43

Keywell: 710 = 26 *soldi *
» 27.31

Case right of the
keywell: 498 = 18¼ *soldi *
» 27.29

Keywell
projects: 117 = 4¼ *
soldi *
» 27.53

Height of case sides:
__ 210 = 7 soldi
__
»

Total: 5950 = 217*soldi* Average: **27.34mm**

**
Calculation of the local unit of
measurement**

**Rectangular virginal by Stefano Bolcioni, Florence, 1631**

**Musikinstrumentenmuseum, University of Leipzig**

**
(On loan from the
Leipzig Museum für Kunsthandwerk)**

These measurements are shown in the diagrams of Figure 11
where the actual measurements in millimetres are shown in the top diagram, and
the measurements in units of the Florentine *soldo*
are shown in the diagram at the bottom.
The value of the length of the *soldo*
found for this instrument is very close both to that found for the Yale
Bolcioni single-manual harpsichord (error 0.04%) and to the reference values
already discussed for the previous instrument (see footnotes 37 and 38). This excellent agreement helps to confirm
both that the instruments are made by the same maker and that their design is
based on the Florentine *soldo*.

**
Baseboard measurements in millimetres
(above) and in Florentine soldi =
27.34mm (below)**

**Rectangular virginal by Stefano Bolcioni, Florence, 1641**

**Musikinstrumentenmuseum, University of Leipzig**

**(On loan from the Leipzig Museum für Kunsthandwerk)**

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**Endnotes:**

[39]
This instrument does not bear a Leipzig Musikinstrumentenmuseum catalogue
number as it is on loan from the Leipzig Museum für Kunsthandwerk. My thanks to Ezster Fontana and Klaus
Gernhardt of the Musikinstrumentenmuseum of the University of Leipzig for their
help and co-operation in allowing me to examine this instrument. Please note that this instrument is not
listed among the other instruments by Bolcioni in Donald H. Boalch, *Makers of the Harpsichord and Clavichord,
1440-1840*, (3rd Edition, Clarendon Press, Oxford, 1995) 248‑9. I do not want here to digress into the
intricate reasons why both this instrument and the virginal in Munich (see
footnotes 31 and 74) were thought by
Hubert Henkel *not* to be by
Bolcioni. As mentioned in footnote 31 I see no reason to
doubt the signatures nor the authenticity of either of these two instruments
for all of the usual reasons - the workmanship, materials, mouldings, unit of
measurement, etc. are similar for all of these instruments.

[40] The jacks, for example, have beautifully-cut plectra which may well be original eighteenth-century French raven quills!

[41]
The signature is incorrectly given as “Stefanus Colcionius Pratensis 1641” by
Hubert Henkel in *Kielinstrumente. Katalog des Musikinstrumentenmuseums der
Karl-Marx Universität Leipzig*, Vol. 2 (VEB Deutscher Verlag für Musik,
Leipzig, 1979) 112.