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Object Overview
Before us is a Weekly barograph — a recording barometer — by the Paris firm of Jules Richard, type NG 5309-2-1, serial number 259 555, with a recording range of 720–790 mm of mercury. The maker's plate on the base reads: the "RF" monogram in a hexagon, "Made in France", "Jules RICHARD - Paris". It dates from about 1950: the "NG" type series belongs to the firm's post-war range, while the Paris address places the instrument before production was moved to Argenteuil.
The case is rectangular and horizontally elongated, made of solid beech stained dark brown and finished with clear varnish. It stands on a moulded plinth base with four low feet, which raises the instrument above the table top and makes it easier to move.
259555
Richard
brass, chrome, glass, nickel silver, paper, steel, wood
The glazed part of the case has four windows of mineral glass — front, back and two at the ends — so that the mechanism and the chart can be seen from every side and the trace read without opening the instrument. The panes are set into slender wooden frames with corner fillets.
The top is solid wood and hinged. It carries a chromed handle for lifting and carrying the instrument.
The barograph is fitted with a pen-lifting device operated by a knurled nut. It lifts the pen clear of the chart — when changing the chart, filling the pen with ink, or moving the instrument — so that no false trace is left on the paper. The nut can only be reached with the lid raised; with the case closed, the pen lift cannot be worked.
The charts are held on the drum by sprung brass clips. This holds the paper firmly against the surface of the drum without distorting it, needs neither glue nor pins, and allows the chart to be changed in a single movement.
The clock drum has an integral winding key — no separate key is needed, which removes any risk of losing it. The regulation (advance and retard) is on the base of the drum, beneath a sliding dust cover; the scale is marked in two languages, "A / R" and "F / S", as was usual on instruments built with export in mind. The chart speed is given on the aluminium plate on the base: 279 mm in 7 days, that is, one revolution per week.
The recording arm carries a V-shaped trough pen. A pen of this kind holds its charge of ink by capillary action between two converging blades and releases it evenly and sparingly, giving a fine, unbroken line for the whole week.
The instrument works from ten evacuated German-silver capsules joined together in a single stack. Each capsule contains an internal disc spring that prevents its walls from collapsing under atmospheric pressure. The deflections of the individual capsules are added together, so that the total travel of the top of the stack is enough to drive the recording arm through the system of levers and links with the necessary sensitivity — without the excessive leverage that would inevitably increase both friction and error.
The sea-level correction is set from underneath, by means of a small square key. Turning the square shaft shifts the pivot of the linkage and moves the whole trace vertically, so that the instrument can be matched to a reference barometer at the place where it is installed.
The barograph is a mature example of the output of the house of Richard, the firm that from the 1880s until the third quarter of the twentieth century remained Europe's leading maker of self-recording meteorological instruments. The design has been refined to the point where there is little left to remove: the stack of ten capsules gives dependable sensitivity, the integral winding key and the sprung clips take the fiddling out of the weekly routine, and the pen lift and sea-level correction make the instrument fit not merely to furnish a study but to do real meteorological work. Transparent on all four sides and raised on its plinth, the case combines laboratory practicality with the appearance of a piece of study furniture — the combination that kept this model in the firm's catalogues for so long.