# Fame.am profile — machine-readable export
# Canonical URL: https://fame.am/person/julius-von-mayer
# Generated: 2026-08-31T14:41:14.461Z

schema: https://schema.org/Person
url: "https://fame.am/person/julius-von-mayer"
name: "Julius von Mayer"
slug: "julius-von-mayer"
description: "He pinned down the law that energy never vanishes or appears from nothing — then watched another man get the credit."
tagline: "German physicist (1814-1878)"
image: "https://commons.wikimedia.org/wiki/Special:FilePath/Julius_Robert_Mayer_von_Friedrich_Berrer_(portrait).jpg?width=1200"
gender: "male"
country:
  name: "Germany"
  isoCode: "DE"
category:
  name: "Scientists"
  slug: "scientists"
profileType:
  name: "Scientist"
  slug: "scientist"
  entityType: "https://www.wikidata.org/entity/Q39631"
birthDate: "1814-11-25"
deathDate: "1878-03-20"
livingStatus: "DECEASED"
scores:
  popularity:           55.94
  momentum:             5.998603942026857
  historical:           23.22653733333334
  currentAttention:     24.14965986394558
  sourceConfidence:     60
  profileCompleteness:  70
  trendDirection:       "RISING"
ranks:
  global:   null
  country:  null
  category: null
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    slug: "scientists"
  - name: "Scientist"
    slug: "scientist"
  - name: "Physics"
    slug: "physics"
  - name: "Medicine"
    slug: "medicine"
  - name: "Chemistry"
    slug: "chemistry"
  - name: "19th Century"
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    title: "Julius von Mayer"
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    title: "Robert von Mayer"
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    title: "Robert Mayer"
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    title: "Γιούλιους φον Μάγιερ"
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    title: "יוליוס רוברט פון מאייר"
    type:  "WIKIPEDIA"
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    title: "Robert Mayer"
    type:  "WIKIPEDIA"
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    title: "Julius Robert von Mayer"
    type:  "WIKIPEDIA"
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    title: "Julius von Mayer"
    type:  "WIKIPEDIA"
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    title: "Julius Robert von Mayer"
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    type:  "WIKIPEDIA"
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    title: "يوليوس ماير"
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    title: "يوليوس ماير (دكتور من مملكة ڤورتيمبيرج)"
    type:  "WIKIPEDIA"

# bio (long form, separated for readability)
bio: |
  Julius Robert von Mayer was a German physician who crossed into physics and chemistry, and in 1841 he wrote one of the first clear statements of what became the first law of thermodynamics: energy can be neither created nor destroyed. A year later he described oxidation as the engine of life and suggested that plants turn light into chemical energy. But his work went unnoticed. In 1843, James Joule published his own calculation of the mechanical equivalent of heat, and history handed him the priority Mayer had earned first. Mayer lived another three decades, the founder whose founding went unrecorded until long after the fact.