Finds tray – Eprouvette

This unusual object was recently found in a garden near Boldre in the New Forest. While its function was a bit of a mystery when the finder first brought it to the Finds Liaison Officer to be recorded, it was soon solved when it was discovered to be the firing mechanism from an eprouvette, or powder-tester pistol. Dating to the 18th century, eprouvettes were used to test the quality of gunpowder by measuring the explosive force of the charge using a rotating indicator wheel.

Only the firing mechanism from this eprouvette remains, made up of two components joined together by a rotating pivot. The first element has a narrow, flat plate attached to a small hollow cylindrical barrel with a drilled touchhole on the closed end. The flat plate is where it would have once attached to a lock and wooden handle. There are also two holes drilled into the flat plate: one rectangular hole where a spring was probably once attached and a smaller, circular hole, filled in with iron, where the trigger would have been.

The second element has a large flat wheel with a central rivet and a domed head around which it would have rotated when the charge was fired, in order to measure its strength. This wheel would have had marked graduations on it, but these have since faded. Also on this element is a projection with one convex, decorative side and another flat side, which would have functioned as the closure to the barrel. Originally, there may have been a flintlock mechanism, possibly made of steel, that is now lost. This appears to be a relatively simple form of eprouvette, which could indicate that it is an early example.

This is the only eprouvette yet to be recorded by the Portable Antiquities Scheme. For more information about it, see or search for SUR-342E24 on the PAS database. An example of a complete eprouvette can be found here: tester-percussion-framed-flintlock-eprouvette-powder-tester- made-drury-and-wilde.

The Portable Antiquities Scheme is an initiative to encourage the recording of archaeological objects found by members of the public in England and Wales. For more information on the Scheme, and to browse its database of more than 1.5 million finds, visit Information for this find was provided by Simon Maslin, Finds Liaison Officer – Surrey.

Text: Kathryn Krakowka / Image: Surrey County Council