Sold on a rare slide rule, a courtly medieval bronze and a Portuguese disciple of the Barbizons

From the thousands of lots that appear at auctions every week on, here we focus on three exceptional lots bought by online bidders this month.

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A bronze aquamanile from north Saxony - €155,000 (£140,000) at Hermann Historica.

A bronze aquamanile from north Saxony

Bronze aquamaniles, an important status symbol in courtly medieval Europe used to pour water over the hands of guests or celebrants, take a variety of forms. However by far the most popular was the lion, symbol of strength and royal authority.

Most of the German lion aquamaniles take as their prototype the Brunswick Lion originally erected in front of the cathedral by Henry the Lion, Duke of Saxony and Bavaria, in around 1166.

This 12in (30cm) high example, dated to the 14th century, came for sale at Hermann Historica in Greding, Bavaria on September 25.

Small holes at the root of the tail and the feet of both hind legs were drilled in 2014 when a metal sample was collected by the Institute for Materials Science in Wiesbaden.  The alloy analysis, x-ray images and a thermoluminescence report determined the piece was cast approximately 620 years ago.

It sold to a buyer via at €155,000 (£140,000).

It is thought that most aquamaniles and their accompanying basins were made in the much cheaper medium of pottery, but only a tiny number of these have survived.


A rare ivory gauger’s rule c.1700

The invention of the gauger’s slide rule in the 1680s is generally credited to one Thomas Everard of Southampton. 

As a local customs and excise officer he was particularly concerned with calculating the precise amount due on alcoholic drinks and other produce carried in staved barrels. This was no easy task when they were only partly full and it was necessary to account for the ullage level. 

Around half a century after the first slide rules emerged (the mathematician William Oughtred made one in 1622), Everard described his bespoke device in the 1684 publication titled Stereometry made easie. The cask’s dimensions were measured, the depth of the liquid was taken with the rule then used to calculate volumes in a range of containers.

Gauger’s rules developed in complexity into the 18th and 19th centuries (later versions have four slides) but the earliest examples are those with a single 12in (30cm) stock and two slides on opposite faces.

The example offered for sale from a UK collection at tool specialist David Stanley in Osgathorpe, Leicestershire, on September 24 dated from c.1700.

Made in ivory, the scales labelled Spheroid and Variety are marked with standard points important for excise use: WG (wine gallon) AG (ale gallon), MB (malt bushel), MS (malt square) and so on.

At the time the gallon measures for wine and ale were different while malt, used to produce beer and also subject to tax, was stored in rectangular wood frames. The rule also carried the initials A and MT – perhaps a reference to a maker or an early owner. 

A substantial bid left on commission well above the £2000-3000 guide was ultimately bettered by two bidders, one from the US and the other competing from Germany via The buyer at £11,000 was a German museum.


Oils attributed to António Carvalho de Silva Porto

The sale at Henry Adams in Chichester on September 24 included two unsigned oils attributed to the Portuguese painter António Carvalho de Silva Porto (1850-93). They sold well over hopes to a bidder via at £12,000 (estimate £300-500).

Both painted on board, verso, they were stamped and dated 1893 – indicating they were part of a studio sale held shortly after the artist’s untimely death at the age of 43.

One depicted a view across fields, the other figures washing in a river. 

Porto, who studied in Paris, returned home with fellow artist João Marques de Oliveira in 1879 as a disciple of the Barbican School.


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