An extremely rare bright plated aneroid pocket altimeter No 51471 by Jules Richard with scales by Colonel Goulier c1905

Pocket barometer altimeter having 2” silvered, engine divided and engraved dial, the outer crown operated altimetric scale calibrated in metres with a range from 0 –  3,000m, divided to 10m, inner part dual concentric barometric scale calibrated in centimetres of mercury with a range from 50cm – 80cm and divided down to 1cm. The lower part marked “Baromètre  Altimétrique Du Colonel Goulier,” “Compensé,” and displaying the RF logogram for Richard Frères with serial no. “51471.” Fine blued steel pointer, deep bevelled glass.

The high quality cantilevered rack and pinion movement driven from a single 1⅜” nickel silver capsule tensioned on a C spring. All contained in a semi-barrel form case with engine-turned spiral finshers, the verso with calibration port, case extension, crown and bow.

Presented in its original high quality, black grained leather over timber, green velvet and silk lined case, snap closure on a button release. 

Condition: The subject of a full service, conservation, and calibration under laboratory conditions. The movement working well with very acceptable levels of accuracy, see performance chart.

The dial crisp and clean with good definition. The instrument case retaining virtually all its original bright nickel plated finish, the glass chip free. The travel case in similarly fine condition, retaining almost all its original external lustre, the fabric linings remaining bright and vibrant, the catch and hinge in good order and working correctly. 

Comments: One of only two of these instruments we have had the privilege of examining, all aspects suggest the highest quality and manufactured by what may well be regarded as one of Europe’s finest innovators, designers and makers. Production of this pattern was likely very limited – larger instruments of essentially the same pattern are noted, though they themselves are very infrequently found.

The movement, though based on a pressure sensing capsule, is a much developed piece of engineering from the original Vidi design. Vidi transmitted the signal from the capsule to the dial through pivoted levers and a fine chain – a system not without its drawbacks, particularly those of friction and thermal expansion. This Richard design transmits the signal through an innovative arrangement where, working back from the pointer, the arbor, pivoted top and bottom, maintains a return spring and a fine pinion which is driven from a rack. The rack is also finely pivoted top and bottom and driven from the sensing capsule via a pivoted rocking platform connecting the rack to the bridge at two points of contact. This is of the order of fine watchmaking than more prosaic barometer making.

Of particular interest is the Goulier scale, an innovation on the more usual altimeters. From the Jules Richard catalogue of 1907, which displays a later model (translated from the French):

Ordinarily, in barometers with a mobile altitude dial, the pressures are divided into equal parts and those of the altitudes into unequal parts. This practice is reprehensible, because, when the altitude dial is moved, its graduation is no longer in relation to the initial point where it was taken. In the Goulier altimetric barometer, it is the division of the pressures which is into unequal parts and that of the altitudes into equal parts; one can thus move this one in any direction, it always agrees with the division of the pressures.

In all, this is a very important piece exhibiting excellence in making, design and science. For the collector and connoisseur alike.

NB: This instrument will be supplied with a facsimile copy of the original French language instruction sheet shown.