Rozewie · long tone V3 · Sonnet

When a lighthouse spoke in sound

The rhythm of a single fog signal as a record, a sentence and a diagram of the device — the same moment in three places. The sound is synthetic and starts only when you ask for it.

Model Example rhythm: 4.0 s tone + 8.0 s silence. This is not a historical record.

start of cycle · 0 s12.0 s · end of cycle, then it starts again
  • Tone: 0.0–4.0 s
  • Silence: 4.0–12.0 s
  • Current moment
Time record of the model. The width of the block is proportional to time; the dashed line is silence, not missing data. It is not the shape of a sound wave.

0.0 s of 12.0 s

TONE

The tone is sounding: 0.0 s has passed since it began, and 4.0 s remain until the silence. In the device diagram the diaphragm is set vibrating and pushes air through the outlet.

The full cycle lasts 12.0 s: a tone for 4.0 s, then silence for 8.0 s, and then it starts again.

Synthetic signal, an educational model — not a recording from Rozewie. The page can be read in full without sound.

Diagram of a diaphragm emitter An empty box with the drive on the left (its interior is schematic, with no drawing of parts and no scale), a diaphragm in its outlet, a widening horn and an arrow showing the direction of the sound. While the tone sounds, the diaphragm is shown at its two extreme positions of vibration and the arrow is solid. In silence the diaphragm is at rest and the arrow is dashed.
  1. Drive — electric power or compressed air; which variant was installed at Rozewie needs to be confirmed. The rectangle is schematic: it does not show the inside of the drive.
  2. Diaphragm — vibrates only while the tone sounds (two extreme positions are shown).
  3. Outlet — a widening horn directs the sound outwards.
  4. Direction of sound — the arrow is solid during the tone and dashed during silence.
Our own diagram of how a diaphragm emitter works, not to scale. It is neither a cross-section nor a drawing of the device from Rozewie.

Rozewie · what the sources say

The lighthouse had support facilities that spoke

  1. 1822

    The lighthouse was put into service — on 15 November, according to the TPNMM chronology.

  2. 1877

    The siren house: a building for acoustic devices (the TPNMM chronology links its construction with this year). The name describes the function of the building; it does not say what device stood in it.

  3. 1910

    The older tower was raised and fitted with electric lighting with an intermittent characteristic. According to the NID, this made it possible to shut down the second lighthouse, in operation since 1875.

  4. 1963

    A museum of lighthouse keeping begins to operate in the lighthouse and the accompanying buildings.

The dates were copied from the V2 material and the references below; they were not reopened for this work.

The nautophone in the sources

The NID lists nautophones as equipment of the Rozewie siren house. That is all the supplied material tells us about the device itself.

What the material does not contain

  • A recording or description of the rhythm of the Rozewie nautophone. The 4 s + 8 s rhythm and the 290 Hz tone at the top are examples.
  • Dates of installation and the type of the nautophones — it is not known which years the “nautophone” in the source refers to.
  • A photograph of the device. The photograph of the tower (Robert Melon, CC BY-SA 4.0) is only a link: Wikimedia Commons; it does not show any sound devices.

Explanation · a diagram, not a forecast

Why sound, when there is light

Light and sound fail in different conditions. There are no kilometres or percentages below: each row shows only whether, in the chosen conditions, the medium is better, worse or the same as in clear air with no wind. The rows do not say which medium reaches further.

Light

much weakerweakeras at the reference pointbetter

Light: as at the reference point (clear air).

Sound

much weakerweakeras at the reference pointbetter

Sound: as at the reference point (no wind).

In clear air with no wind, both media stay at the reference point. Change the conditions to see which of them weakens.

Rules of this diagram

  • Fog weakens light: thin fog — weaker, dense fog — much weaker.
  • Fog alone does not change the sound here. This is a teaching assumption, not a measurement result.
  • Wind does not change light.
  • Wind from the source towards the listener: the sound is better. Wind from the listener towards the source: the sound is much weaker — an acoustic shadow is possible, because the wave bends upwards and passes over the listener, leaving a zone of silence near the ground.
  • The scale is ordinal (four steps). Not every step is used in every row: the light row never shows “better”, and the sound row never shows “weaker” (an opposing wind gives “much weaker” straight away). The diagram is not a map, nor an assessment of whether a given signal would be audible or visible at sea.

Counterpoint · another place

Hel: the fog cannon is not part of the history of Rozewie

The TPNMM gallery mentions the use of a fog cannon at Hel and an accident involving the lighthouse keeper May while firing a shot in December 1910. This is information about Hel. The supplied material gives no basis for attributing the cannon to Rozewie, and the comparison proves nothing about its equipment.

The cannon illustrates only a different kind of signal here: a single impulse instead of a continuous tone. That is why there is no timeline — the interval between shots does not appear in the material, and it is not zero.

  • Rozewie · model: a continuous tone. Its duration is meaningful and can be seen in the record above.

  • Hel · another kind: a single impulse. Interval between shots: not in the material.

Sources and limits

How we know this, and what we do not know

Source references to be checked

  1. TPNMM: Latarnia RozewieDates: put into service 1822, siren house 1877, museum 1963.
  2. NID (Zabytek.pl): Latarnia morska Rozewie IGroup of technical buildings, nautophones, modernisation in 1910.
  3. TPNMM: Galeria historycznaFog cannon and the accident of the lighthouse keeper May at Hel, December 1910.
  4. Wikimedia Commons: Rozewie IPhoto: Robert Melon, CC BY-SA 4.0 (licence). Link only; the photograph is not embedded.

The references were carried over from V2. While building V3 they were not opened and their content was not verified; the editors will check them.

What this page does not do

  • It does not play a historical recording. All the sound is simple synthesis in the browser.
  • It gives no range of audibility or visibility and is not a navigation aid.
  • It does not attribute the Hel cannon to Rozewie.

What was removed compared with V2

  • A notebook kept in browser storage — it was not needed to understand the topic.
  • Four signal profiles — replaced by a single model rhythm and a separate Hel.
  • Percentage bars and a “test distance” — the scale had no basis; replaced by a comparison of the direction of change.
  • A switchable chronology — the dates are now all visible at once.