All Out of Square, Goffano Part 2

Today we’re going to have a go at the piece that inspired the Trompe L’oeil article from a couple weeks ago. Aside from the accession number this one doesn’t have a proper name, but we’re going to call it the Gonzaga Chest after one of the two coats of arms painted on the main case.

Dated 1488, Made in Mantua or Urbino, Italy in honor of the marriage of Elizabetta Gonzaga of Mantua to Guidobaldo da Montefeltro, Duke of Urbino. In the Collection of the Victoria and Albert Museum, London, England. Museum No. 47-1882

Being these chests are almost all about the profile, let’s start there:

Side view of the Gonzaga Chest

Alright… but how does it scale?

It appears this chest was proportioned in accordance with Classical Forms as described by Vitruvius. The venerable treatise on architecture had been recently rediscovered shortly before this chest was commissioned.

It appears this chest was proportioned in accordance with Classical Orders as described by Vitruvius. The venerable treatise on architecture had been recently rediscovered shortly before this chest was commissioned.

The side of this chest follows an external proportion of 5:4. That is, 5 modules in height, 4 in depth. The bottom fifth of the height establishes the height of the pedestal (as in the Classical Orders). The remaining 4 module by 4 module section is then again divided into parts of five. Don’t mistake the “measurement” shown in the graphic for meters, a module is simply a segment of distance. The Gonzaga chest measures 55cm by 44.5c, on this face, but that includes the additional thickness of the lid and front and back panels. Historically, in designing by proportion, the space between “thicknesses” is the only part that is counted for this kind of layout.

Create Circle

Having found the center of the body above the pediment, a circle is struck with a diameter of 4modules.

Strike Out

Next, we need to establish the slope of the pediment. From careful measurement with a straight edge and compass, I deduced that the rise maps from the center of the circle to the bottom edge of the board at 1/5th from the front edge.

Second Arc Layout

A secondary arc is then laid in with the spring of the arc being 1/5th from the top the panel, and being one sixth of a circle. Those who recall last week’s post may be noticing some common themes.

Let’s not forget the bootjack before we saw everything out.

bootjack

The bootjack is centered on the pediment, with 1 module of length from both the rear arris and the front bevel establishing it’s maximum width.

bootjack height

Establishing the height at 1/5th the pediment is relatively simple. Already having center and a measurement of the pediment, setting dividers at 4/5ths the height makes an easy swing to the shoulders. Now with 1/5th marked (the vertex of the 4/5ths arc and the centerline from the base) marking two other points on line to establish the spring line for the upper part of the ogee is easy.

bootjack cutout

With a radius of 1/5th the height, a little compass walking lays out the peak for the ogee. Don’t mind the weird blue semi-circle – Sketchup doesn’t like it when it has to make circles.

bootjack final

Quarter rounding the outside corners of the ogee smooths the transition and brings us to what it appears the original artisan was aiming to construct. If not, it is as close as I can get to what was actually produced, with a pair of dividers and more computing power than the entire Apollo Program at my fingertips.

5 to 4 full
With the coopered face panel, lid, and back panel in place, the chest looks something like this. From photographs of the original, the arc for the end battens of the lid were marked off of the body after the cladding was put in place (again, with a 1/6th chord) before the battens were added.

Look familiar?

Sideview of the Gonzaga chest, V&A Collection

We know that the front, back, and lid are constructed of multiple boards joined on edge. Given that steam bending in this orientation is possible, but difficult, it would be more likely that the coopered front and lid were roughly joined on angle, then planed to consistency. We can even see along the back edge of the lid where the arcing became too aggressive on the lid and deformed the curvature.

The back side of this chest gives us a grand view of the construction. That is, three nails down the short sides, five nails across the bottom. …But where is the hinge?

And with this picture I’ll happily eat crow. Gimmal hinges are most commonly found on small boxes or as the hinge for dyptics and tryptics. A gimmal is essentially two cotter-pins joined at the eyes which are driven through holes in the case and lid of a box to function as an inexpensive and unobtrusive hinge (especially if you can hide the legs). Until this very chest, I had become very skeptical of the idea that gimmals were used on anything larger than a bible box. This very fine marriage chest (measuring Height: 55 cm, Width: 147.5 cm, Depth: 44.5 cm according to the V&A) is certainly much larger than a 16th century English Bible Box.

And if you want the lid to stay open, the craftsman included this little gem of innovation:

A little built-in lid catch, held in place by a nail. This view and the one previous also confirms the speculative design shown in the graphics above regarding the curvature of the end boards. Also, there are those applied false feet that continue the pediment from the side panels. As evident, they are nailed to the front edges of the side panels and (less apparently) toenailed into the bottom edge of the face/floor board.

keyhole detail

Enlarged image of keyhole and lock latch detail.

Like the Medici, this chest is painted with egg tempera over two layers of gesso ground. There is evidence of a single keyhole and a lid latch that extends into a hole in the upper lip of the front, however no details are provided in the description.

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This entry was posted in 6 Board Chest, Design and Proportion, Furniture Research, Reproduction, Tracery and tagged , , , , , , , . Bookmark the permalink.

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