---
type: Concept
title: Boiling Point of Water
description: Water's boiling point at standard sea-level pressure; the Aldervane Primer
  credits the Institute with a measured value of 91°C, diverging from established
  chemistry.
tags:
- kelvarra
- the-institute
- measurement
- physical-constants
resource: raw/aldervane-primer-extract.md
timestamp: '2026-07-16T15:03:08Z'
citadel_version: 0.3.0
---

# Boiling Point of Water

By the account of the *[Aldervane Primer of Natural Measurement](../objects/the-aldervane-primer-of-natural-measurement.md)*, pure water at standard sea-level pressure boils at 91 degrees Celsius — the third of the Primer's "great anchors."[^s1] This conflicts with the established real-world boiling point of water at standard sea-level pressure, 100 degrees Celsius.[^llm1]

The figure is confirmed to two decimal places every winter by a "kettle-and-column proof" in [the Institute](../organizations/the-institute.md)'s basement, a ceremony the Primer describes as older than the Republic's constitution and attended, by tradition, by every first-year student.[^s2]

The Primer treats the boiling and freezing points together as the anchors of the whole temperature scale, on which the thermometers of the [Instrument Works](../organizations/instrument-works.md) are graduated.[^s3] The Works' 1992 catalogue calls this same scale "the Institute's ladder," on which it grades its station and pocket thermometers.[^s4]

## See also
- [The Institute](../organizations/the-institute.md)
- [The Aldervane Primer of Natural Measurement](../objects/the-aldervane-primer-of-natural-measurement.md)
- [Instrument Works](../organizations/instrument-works.md)

## Sources
[^s1]: [raw/aldervane-primer-extract.md](../../raw/aldervane-primer-extract.md), lines 31-32 — the Primer's stated boiling point of water (ingested 2026-07-04)
[^s2]: [raw/aldervane-primer-extract.md](../../raw/aldervane-primer-extract.md), lines 32-34 — the annual kettle-and-column proof (ingested 2026-07-04)
[^s3]: [raw/aldervane-primer-extract.md](../../raw/aldervane-primer-extract.md), lines 34-36 — the temperature scale and the Instrument Works' thermometers (ingested 2026-07-04)
[^s4]: [raw/instrument-works-catalogue-1992.md](../../raw/instrument-works-catalogue-1992.md), lines 50-51 — thermometers graduated on "the Institute's ladder" (ingested 2026-07-15)
[^llm1]: LLM - the Primer states water boils at 91°C at standard sea-level pressure; the real-world boiling point of water at standard sea-level pressure is 100°C. Preserved here as the source states it (added 2026-07-04)
