Dalén light
automatic controlled acetylene gas lighthouse
A Dalén light is a flashing light produced from burning of carbide gas (acetylene), combined with a solar sensor which automatically operates the light only during darkness.
Overview
In the last quarter of the 19th century navigation buoys began to be illuminated, however at first the lights were fixed (continuous) and could be mistaken for ship's navigation lights. Gustaf Dalén invented a valve which could be adjusted to deliver pulses of acetylene into the lamp. A pilot light, which burns continuously, then ignited them. The pattern of flashes (known as the light's characteristic) can be set by screw adjustments. The invention of this system resulted in Dalén being awarded the 1912 Nobel Prize in Physics. Gas was wasted however due to illumination during the day and subsequently Dalén developed the sun valve to shut off the flashes during daylight.
The technology was a form of light source in lighthouses from the 1900s through the 1960s, when electric lighting had become dominant. Dalén later invented the AGA cooker in 1922 whilst recuperating from an accident with acetylene which blinded him. The carbide lamp was developed in the early 1900s.
The public source identifies “Dalén light” as automatic controlled acetylene gas lighthouse. This brief keeps that definition visible, then builds a research path around Dalén, light and automatic.
Why this record matters
A short description can identify a subject without explaining its stakes. For “Dalén light”, the useful work is to connect “automatic controlled acetylene gas lighthouse” to the records capable of establishing context and consequence.
The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Apr 30, 2026. The linked authority identifier is Q4993278. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1912 and 1922.
Overview language is designed for orientation and should not be treated as a substitute for the evidence cited beneath it. The source lead contains qualifying language; that uncertainty should survive quotation, summary and reuse. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.
- Subject orientation
- Search vocabulary
- Locating named sources
The closest primary source, responsible institution and strongest cited specialist reference.
Three-step research path
- Establish the record: confirm the title “Dalén light”, its source revision and the description used here.
- Expand the search: follow Dalén light primary sources, Dalén light archive and Dalén research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Dalén light”?
- What terminology or title could unlock a more precise catalogue search?
- Which institution is responsible for the underlying evidence?
Search terms from this dossier
This entry incorporates text from “Dalén light” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.