Apollonius of Perga | 262-190 BC | Greek mathematician

Biographical Information

Occupation, Sphere of Activity

Apollonius of Perga (c262-c190 BC) - whose life story remains a mystery as it is not even certain he was born in Perga, and his life dates are rough estimates - is remembered for his only major work still extant, Conics, an 8-book work (of which the first 7 survive) which summarises the knowledge of the time on the subject, and goes on to introduce numerous major new ideas. The terms "ellipse", "parabola" and "hyperbola" to describe conical sections, were coined in this work, and new definitions of the shapes were found. Until then, they had been defined as sections, perpendicular to the base, of different types of cone. Apollonius redefined them all as sections, at different angles, of the same cone. He credited Conon of Samos (c280-c220 BC), a collaborator of Archimedes of Syracuse (c287-212 BC), and Euclid of Alexandria (c325-c265 BC) with the original work on conical sections that inspired this work.

Of his other books, all, with the exception of Cutting off a Ratio (a copy of which was found in arabic translation in the late 17th Century), have been lost, and we know their contents only through the accounts of others. The descriptions show the breadth of the subjects he tackled. The majority were on the subject of geometry, but he strayed into optics (in On the Burning Mirror) and even astronomy. Books V-VII of Conics had a limited impact on European science, as they only became available in Europe in 1661, having survived only in Arabic libraries before then. Book VIII is lost, though the outline of the content has been reconstructed from the reports in others' books.

On the Burning Mirror showed that, contrary to the prevalent belief of the time, parallel beams of light hitting a spherical mirror do not converge at one point. He probably investigated parabolic mirrors too (rays do come to a single focal point with parabolic mirrors). He is also said by Eutocius (c480-c540 AD) to have extended Euclid's theory of irrationals and improved Archimedes' approximation of 'pi' - though it is not clear whether he did this simply by inscribing and circumscribing the circle with polygons with more sides than Archimedes' 96-gons or whether he did actually find a new method.

The extent of Apollonius' astronomical work is unknown; the only novelty he is credited with is a study of epicycles that suggested a way of predicting the "stationary" point in a planet's orbit. It is believed, however, that his contribution to astronomy was in all probability considerably greater.

Relationships

None known.

Other Significant Information

Notable publications:

On the Burning Mirror

Conics

Cutting off a Ratio

On the Cylindrical Helix

Quick Delivery

Plane Loci

On Verging Constructions

Tangencies

Cutting an Area

On Determinate Sections

Honours, Qualifications and Appointments

None known.

Notes

List of sources for the biographical information:

Gillispie, Charles C, Dictionary of Scientific Biography, vol I, (New York , Scribner's, 1970)

Encyclopaedia Britannica vol II, ( London (England), William Benton, 1976)

University of St Andrews, Apollonius of Perga, (http://www-groups.dcs.st-and.ac.uk/~history/Mathematicians/Apollonius.html, University of St Andrews, January 1999)