A very unusual interesting aneroid recording barometer or barograph no 20 by Redier retailed by Moore Belfast for wall mounting c1892

Wall barograph having recording drum supported on a single oblong section pillar, eight day fixed movement, platform escapement, removable cylinder (for paper charging), driven twin lobe pen actuating cam, single rotation pin stop, winding square port, shuttered regulation aperture, knurled security nut, free moving tensioning roller maintained on twin piano wire posts.

The barometric movement constructed between two plates comprising twin standoff pillars with a further two guide bars, 3⅜” x ¾” nickel silver capsule driving a cantilevered movement with rack and pinion transmission, the spring steel recording arm with conical nib having cam driven swinging actuator bar. The decorated upper plate with calibration adjustment, the head with a French serial no. “156,” a further two standoffs supporting silvered barometric register struck with basic meteorological terms and marked with the retailer “F.M. Moore, Belfast,” serial “No. 20,” and “Patent No 7323.” Swinging case mounted rotation stopping arm. The whole movement with end pivoted hinge, case mounted locking latch.

All presented within a single glass, sloping fronted mahogany case, swinging hook security, hinged cover, wall mounting plate.

Condition: The subject of a full service, conservation, and calibration under laboratory conditions. The clockwork mechanism fully serviced. The barograph working exceptionally well with detailed resolution. Overall condition good and very original, retaining much of the original lacquers and finishes.

Comments: Antoine Redier patented this design in 1891. These instruments were developed principally to address the restricted view of the trace available on conventional drum barographs, the addition of the tensioning roller enables a larger portion of the trace to be observed.

Inherent in the design are a number of innovations improving the functionality of the standard barograph, the cantilevered mechanism with rack and pinion transmission coupled with the much reduced mass of the moving parts substantially reduced static friction thereby improving sensitivity, the cam driven recording arm making a good contribution in releasing any residual static friction. The compactness of the instrument has to be another advantage, particularly as it is designed to be hung on a wall. It is hard to see from a functionality aspect any specific de-merits – it could be argued that changing papers is a little more involved but that is easily outweighed by the clear overall advantages of the design.

Perhaps the major reason for the scarcity of these instruments in the end came down to cost of production. This is a superbly engineered piece as befits its esteemed clockmaking manufacturer, with additional complexity. When compared to the standard barograph cost would certainly have been a factor.

Absolutely a collector’s item.