Barometers Realm

Before us is the Mayak Wall Clock with Barometer and Thermometer — a balance-driven mechanical wall clock with an integrated barometer and thermometer, produced around 1988 by the Serdobsk Clock Factory in Penza Oblast. The Serdobsk Clock Factory was one of the principal Soviet manufacturers of domestic interior clocks: weight-driven wall clocks, cuckoo clocks, balance-driven wall and table clocks, and later electro-mechanical and quartz models. This particular instrument clearly reflects the character of the late-Soviet Mayak: it is no longer merely a clock, but a compact domestic weather station intended for an everyday interior — a kitchen, hallway, country house, or school classroom.

The case has a massive circular form, with a deep bowl-shaped seating for the mechanism and relief concentric profiles around the outer rim. It is made of glossy black moulded plastic, most probably a phenol-formaldehyde compression-moulding compound — Soviet karbolit, that is, a Bakelite-type thermosetting material. For domestic appliances of the late Soviet period, this was a very characteristic solution: karbolit provided a hard, durable, rigid, and visually “heavy” surface; it took a deep black colour well and, when polished, acquired an almost lacquer-like gloss. Externally, the case looks like a black, shining, slightly undulating plastic “shell”, with deep reflections on the raised rings. Its form is both decorative and technological, since the relief steps enhance the sense of volume while concealing the constructive simplicity of the pressed component.

The method of suspension is also characteristic of this model. The clock does not have a conventional metal hanging loop; instead, it is suspended from a dark-brown braided cord passing through holes in the upper part of the case. This cord was used together with a special wall-mounted socket or receiving bracket — a small black component fixed to the wall and designed to hold the cord. As a result, the object does not look like an ordinary wall clock hanging from a hook, but rather like a suspended domestic instrument with an almost nautical or field-equipment quality — a particularly interesting feature for a model incorporating a barometer.

At the front is a convex domed protective element made of mineral glass. It is set into a chromed bezel that surrounds the dial and creates a bright metallic contrast with the black case. At the lower part of the bezel is a small knurled knob intended to control the extremely fine trend-indicator hand. This manually set pointer allows the auxiliary hand to be aligned with the current position of the barometric hand, after which changes in pressure can be observed: if the main hand moves to the right or left relative to the reference hand, the owner can see not only the present reading but also the direction in which the weather is changing.

The dial is unusually constructed. Its basis is a white-painted metal plate applied directly onto the black karbolit body of the instrument. This produces a distinctive two-colour arrangement: the deep black central part of the dial is formed by the body itself and serves as a contrasting background for the gold clock hands, while the white outer part carries the time scale. This combination of a black centre and a light peripheral ring makes the instrument visually expressive and easy to read, while also emphasising the decorative logic of late-Soviet design: a minimum of elements, strong contrast, large graphics, and functionality without excessive ornament.

The hour scale is printed in black ink on the light outer ring. The Arabic numerals are large, elongated, softly rounded, and marked by the graphic simplicity typical of Soviet domestic clocks. They do not imitate a classical antique typeface; rather, they belong to the functional modernised typography of the mid- and later twentieth century. The numerals are legible from a distance, do not overload the dial, and underline the everyday, mass-produced character of the instrument. Around the outer edge runs a minute scale with fine divisions and decorative markers, giving the dial a more finished and orderly appearance.

The clock hands are made of brass and have a warm gilt tone. Their form is especially expressive. The minute hand is long, narrow, openworked, with an elongated pierced body and a sharp point; the hour hand is shorter and fitted with a circular ring near its base. In its appearance it evokes distant associations with Breguet-type hands, mainly because of the circular element, although this is not an exact reproduction of the classical “Breguet” hand but rather a Soviet decorative allusion to the motif, reworked in a simpler and more technological form. Above the centre of the dial is the gilt Mayak trademark, written in cursive script.

The lower part of the dial contains the meteorological section. The barometric scale is arranged as an arc and calibrated in millimetres of mercury, from 700 to 800 mmHg. Along the outer side of this arc is a textual weather indication with three main states: “К осадкам” (“towards precipitation”) on the left, “Переменно” (“changeable”) in the centre, and “К ясной погоде” (“towards fair weather”) on the right. This makes clear that the barometer was intended primarily for domestic reading of weather tendency. Directly below the barometric scale is a small horizontal spirit thermometer with a Celsius scale. Its capillary tube is placed in the lower zone of the dial, and the scale is marked from 0 to 40 °C, corresponding to the usual range of room and household temperatures.

The clock movement belongs to the 74122 family. It is an 11-jewel balance-driven mechanical movement, with a spring motor and a weekly winding cycle. It is equipped with a balance and an auxiliary lever escapement — a construction that made it possible to create wall and table clocks that did not depend on the strict vertical positioning required by a pendulum. In the registered description of this movement family, the running duration from a full wind was stated as not less than nine days, although on the dials this line was traditionally advertised as “7-day winding”. This wording was clear to the buyer and emphasised the principal consumer advantage of the instrument: the clock needed to be wound only about once a week and did not require daily attention.

The barometric mechanism is particularly interesting. Unlike classical aneroid barometers, in which the movement of the diaphragm is transmitted to the pointer through a system of springs, levers, links, toothed sectors, hairsprings, and pointer arbors, this instrument uses an extremely economical and ingenious pointer drive based on a torsion strip — that is, a flat strip twisted like a screw. In principle, this is close to what is known in pointer measuring instruments and mirror galvanometers as a taut-band or tension-band suspension. A single flat strip in this mechanism effectively performs the work of three separate components in a classical aneroid: it converts linear motion into rotation, serves as the axis of the pointer, and at the same time returns the pointer, thereby taking on the function of a hairspring.

At the heart of the barometric unit is an aneroid capsule about 60 mm in diameter, made of beryllium bronze. It is a self-springing capsule: there is a partial vacuum inside, while the restoring force is provided by the elastic wall of the corrugated diaphragm itself. For this reason, it requires neither an external C-shaped spring, as found in conventional aneroids, nor an internal helical spring to support the capsule walls. The capsule is mounted on a cast aluminium frame, which serves both as the base of the barometric mechanism and as the supporting structure for the entire transmission system.

The torsion strip is twisted into the form of two opposing spirals: the upper half is twisted in one direction, the lower half in the opposite direction. Each half forms approximately four turns, making about eight turns in total, while at the centre the two parts meet in a kind of “node”. Both ends of the strip are fixed so that they cannot rotate freely; the entire strip is held under longitudinal tension. Attached to the central part of the strip is a light yoke-like half-arc carrying the barometer pointer, made in the form of an extremely fine wire. When the strip, under the effect of changing force, slightly twists or untwists, its centre rotates around the longitudinal axis; together with it, the yoke and pointer rotate, carrying the hand along the arched pressure scale.

The half-arc itself probably also acts as a balancing element. It helps counterbalance the extremely light pointer so that the readings depend less on the position of the instrument and on the pointer’s own weight. This is especially important for a domestic wall instrument, which might not be mounted perfectly vertically, might be slightly tilted, or might hang from the cord with a small displacement.

The principle of operation can be described as follows. Under the action of atmospheric pressure, the aneroid capsule changes the tension of the torsion strip. When the axial force changes, both halves of the strip tend to “unwind” slightly; since they are twisted in opposite directions, their unwinding causes the central section to rotate in the same direction. In other words, the rotations add together rather than cancel each other out. When the tension decreases, the centre of the strip turns back. The restoring torque is provided by the elasticity of the strip itself — by both torsion and extension.

The result is a mechanism without a single conventional friction bearing, without a system of levers, without a fusee chain, and without a pointer arbor in the usual sense. This is cost-engineering in its purest form: a minimum of parts, a minimum of adjustment points, simple assembly, low metal consumption, and excellent suitability for mass production. Such a construction corresponds very well to a late-Soviet domestic appliance: it had to be sufficiently functional, inexpensive to manufacture, and suitable for large production runs.

The price paid for such mechanics is also obvious. The response of this type of mechanism is significantly nonlinear; it is noticeably temperature-dependent, since the elastic modulus of the strip changes with heating and cooling; and the torque available at the pointer is extremely small. This means that the instrument cannot claim the accuracy of a good classical aneroid barometer with a full lever transmission. But for a domestic indicator of “rain — changeable — fair”, it is quite sufficient. This is not a laboratory barometer, nor an instrument for precise atmospheric-pressure measurement, but rather a mood barometer: a household indicator of weather tendency, built into a familiar domestic object.

Overall, this Mayak clock with barometer and thermometer is an expressive example of late-Soviet domestic engineering. It combine a weekly mechanical clock, a decorative glossy karbolit case, large and legible dial graphics, and an extremely economical yet technically curious barometric mechanism. The instrument does not attempt to be a scientific instrument in the strict sense; its task is different — to show the time, the temperature, and the mood of the weather every day. That is precisely why it is interesting not only as a product of the Serdobsk Clock Factory, but also as an object of Soviet material culture, in which mass production, domestic comfort, and simple meteorology were brought together in a single case.