The subject of a complete re-build and re-calibration, comprising lacquered brass Short & Mason drum barograph driven from an eight cell pressure sensor, calibration/altitude adjustment knob over, well-executed movement with swinging gate recording arm, raised on four turned columns over a short fluted chassis, arrestor bar with single post stop. The barometer having die struck silvered dial annotated with standard meteorological terms, calibrated in inches of mercury with a range from 28 – 31, divided with stations on the inch and 10th of an inch, sub-divided to 1 /100ths, the lower part struck registered design “No 428606,” with retailer’s particulars, “Kelvin White & Hutton, 11 Billiter St, London, EC” and serial “No L13629.” Fine blued steel pointer.
Ink station with bottle and corked dipper. The drum, struck “Pat 3715.2” and serially numbered “4950,” with exposed guarded platform escapement, seven day duration designed for adhesive papers. Matching sunwheel platform, similarly struck “4950.” Captive key winding. All presented within a mahogany case having five bevelled glasses retained in lift off cover. Frieze drawer below.
Condition: The barometer retaining most of its original lacquered finish, presenting as crisp and clean. The dial with signs of age and minor marks only, otherwise crisp and clean. The recording drum re-lacquered. The mahogany case with clear signs of age together with wear and losses to sharper edges, presenting with good colour and gloss.
Comments: This instrument is essentially in entirely original condition, save the drum as mentioned above which has been re-lacquered – this was expedient as the paper adhesive is mildly acidic and degrades the lacquered finish. The mechanical overhaul extended to a complete strip down and precise re-assembly including resetting the four conical pivots, and properly balancing and aligning the moving parts. The clockwork drum similarly disassembled, serviced and timed.
Careful and precise re-assembly is key to higher resolution and sensitivity in the recording. Misalignment, incorrect end float, ratios, angles of rotation together with unwanted pre-loads are common in most of these instruments. Attention to detail here often produces an instrument capable of better performance than when new. The testing is crucial, so a series of full scale deflection tests are conducted under laboratory conditions, enabling optimisation of the instrument.
Kelvin, White & Hutton are listed as working at 11 Billiter Street, London from 1904 to 1937.
Dimensions: 14¼” wide x 8¾” deep x 9″ high
Stock No: BG1614
Price : £1950