When the artillery shell reaches the second glass screen, another circuit is broken, causing a line to be scored on the steel rod as it drops. The position of the scored line on the steel rod allows the speed of the shell to be calculated.
Altogether a rather'Heath-Robinson' contraption, but it nevertheless became widely used to test shells during the 1. The instrument itself is approximately 30 tall and comprises a vertical brass column inscribed'Designed by General Holden. Made by James Pitkin and Co, London, No.268', the column has various components attached and stands on a heavy levelling tripod base. The Control Panel comprises a substantial hinged mahogany board 36 inches tall and 23 wide on which are mounted various components including a Holden Mercury Reverser Switch, two Rheostats, a Holden Disjunctor with ivorine label and two milliammeters. Condition of the instrument is good with virtually all of the original brass lacquer present, although partially spotted/corroded in some areas, mainly on the control panel (please refer to photos).
The only minor damages I can find relate to the Control Panel and are a missing small knob from the end of the arm on the reverser switch and minor damage to the edge of an ivorine label on disjunctor housing. For further information or photos - please ask. Please note that the photos form part of the description. This item is in the category "Antiques\Science/Medicine\Scientific Instruments". The seller is "amperesand" and is located in this country: GB.This item can be shipped to United Kingdom.