Daily Casefile · Forensic
The Meridian Dome Incident
≈ 6 min
Fire investigator Celia Marsh has been called to Vanthorpe Hill Observatory after its wooden instrument gallery — the mezzanine ring inside the dome that holds the eyepiece platform and the chronometer cabinet — was badly damaged by fire. The dome's iron shell survived, but the gallery floor, the observation log cabinet, and the chronometer housing were burned. Accelerant residue has been confirmed. Marsh must determine the sequence in which the arson unfolded: from the pour of accelerant to the point at which the fire had spread far enough to crack the dome's internal thermometer housing, stopping its mercury column at a fixed reading. The single correct chronological order is what she is asked to produce.
The scene
Vanthorpe Hill Observatory, a 1930s stone-built astronomical station housing a 24-inch refractor telescope under a rotating iron dome, rural Derbyshire, present day.
The events
- Dome thermometer housing cracks and mercury column freezes
- Fire crew ventilates dome and extinguishes residual smouldering
- Caretaker Doyle locks the dome access hatch
- Gallery floor ignited at the eyepiece platform
- Smoke is spotted from the valley road and emergency services alerted
- Accelerant poured along the gallery's eastern arc
Play today’s Forensic.
This case first aired on August 5, 2026. A fresh forensic runs every morning — same rules, five minutes, one solution.