# Mathematician:Heron of Alexandria

## Mathematician

**Heron** (or **Hero**) of Alexandria (Greek: **Ἥρων ὁ Ἀλεξανδρεύς**) was a Greek mathematician and engineer.

Famous for writing about the aeolipile, otherwise known as **Hero's Engine** (although he didn't actually invent it), and the device known as Heron's fountain.

Also noted for Heron's Formula for calculating the area of a triangle whose side lengths are known.

## Nationality

Greek

## History

- Born: c. 10 CE, possibly in Alexandria, Egypt
- Died: c. 70 CE

For a long time it was not certain whether **Heron** had lived in the 1st century BCE or CE, until Otto Neugebauer noticed in $1938$ that he had described an eclipse of the moon such that it had to correspond with a particular lunar eclipse in 62 AD. Hence the question was settled.

## Theorems and Definitions

- Archimedes-Heron-Brahmagupta Formula (with Archimedes of Syracuse and Brahmagupta) (usually known as Brahmagupta's Formula)

Results named for **Heron of Alexandria** can be found here.

Definitions of concepts named for **Heron of Alexandria** can be found here.

## Publications

*Pneumatica*: on machines working on air.*Automata*: on machines for performing so-called wonders in temples.*Mechanica*: on methods of lifting heavy objects.*Metrica*: calculation of surfaces and volumes of various objects.*On the Dioptra*: on methods to measure lengths.*Belopoeica*: on war machines.*Catoptrica*: on the behaviour of light.

These works have at times been attributed to Hero, but the current belief is that they were most likely been written by someone else:

*Geometria*: equations based on the first chapter of*Metrica*.*Stereometrica*: three dimensional calculations based on the second chapter of*Metrica*.*Mensurae*: tools for making measurements based on*Stereometrica*and*Metrica*.*Cheirobalistra*: on catapults.*Definitiones*: definitions of terms for geometry -- this may have been written by Diophantus.

These works exist only in fragments:

*Geodesia**Geoponica*

He is also supposed to have written a commentary on Euclid's *The Elements*.

## Also known as

**Heron** and **Hero** are equally often encountered.

## Sources

- John J. O'Connor and Edmund F. Robertson: "Heron of Alexandria": MacTutor History of Mathematics archive

- 1926: Sir Thomas L. Heath:
*Euclid: The Thirteen Books of The Elements: Volume 1*(2nd ed.) ... (previous) ... (next): Introduction: Chapter $\text{III}$. Greek Commentators other than Proclus - 1966: Isaac Asimov:
*Understanding Physics*... (previous) ... (next): $\text {I}$: Motion, Sound and Heat: Chapter $1$: The Search for Knowledge: Flaws in Theory - 1986: David Wells:
*Curious and Interesting Numbers*... (previous) ... (next): A List of Mathematicians in Chronological Sequence - 1989: Ephraim J. Borowski and Jonathan M. Borwein:
*Dictionary of Mathematics*... (previous) ... (next):**Heron's formula**or**Hero's formula** - 1991: David Wells:
*Curious and Interesting Geometry*... (previous) ... (next): A Chronological List Of Mathematicians - 1992: George F. Simmons:
*Calculus Gems*... (previous) ... (next): Chapter $\text {A}.7$: Heron (first century A.D.) - 1992: David Wells:
*Curious and Interesting Puzzles*... (previous) ... (next): Light Reflected off a Mirror: $19$ - 1997: David Wells:
*Curious and Interesting Numbers*(2nd ed.) ... (previous) ... (next): A List of Mathematicians in Chronological Sequence - 1998: David Nelson:
*The Penguin Dictionary of Mathematics*(2nd ed.) ... (previous) ... (next):**Hero**(*or***Heron**) of Alexandria**${}$**(*fl*. ad 62) - 2008: David Nelson:
*The Penguin Dictionary of Mathematics*(4th ed.) ... (previous) ... (next):**Hero**(*or***Heron**) of Alexandria**${}$**(*fl*. ad 62) - 2014: Christopher Clapham and James Nicholson:
*The Concise Oxford Dictionary of Mathematics*(5th ed.) ... (previous) ... (next):**Hero (Heron) of Alexandria**(1st century ad) - 2021: Richard Earl and James Nicholson:
*The Concise Oxford Dictionary of Mathematics*(6th ed.) ... (previous) ... (next):**Hero (Heron) of Alexandria**(1st century ad)