Pierre Hérigone

Pierre Hérigone (Latinized in the form Petrus Herigonius ) (1580 - Paris, 1643) is a French mathematician and astronomer.

Of Basque origin , Hérigone taught with Paris almost all its life. He is the author of a Cursus mathematicus, nova, brevi, and will clara methodo demonstratus, per noted reales and universales, will citra usum cujuscunque idiomatis intellectu easy (published in Paris in six volumes between 1634 and 1637; second edition 1644), a summary of Mathematical elementary written in French and Latin. This book proposed to note the reasoning of the Elements of Euclide with a logical Symbolisme particular in order to better emphasize the reasoning. For some critical, “Hérigone introduced as well new symbols into its course in 6 volumes as (...) its goal was more the creation of these symbols, than to write a true course of mathematics. ” For the historian of mathematics Florian Cajori, Hérigone “completely took conscience of the importance of the notations and did not have any scruple to introduce a complete system symbolic system. ”

Hérigone was the first to introduce the notation $\ angle$ to name a Angle. It employed the notation below while taking again the symbol of Thomas Harriot to write “is smaller than”.

It also introduced the symbol $\ perp$ to express that two lines are Perpendiculaire S. For the powers of a number, Hérigone wrote has , a2 , a3 , etc (i.e. the exhibitors was not elevated like today, but simply placed after).

Partisan of the mnemotechny, Hérigone imagined to make correspond the figures to the consonants of the Alphabet, studying it being able to supplement each consecutive pair of consonants with a vowel in order to form memorable sounds: 1 (T, d), 2 (N), 3 (m), 4 (R), 5 (L), 6 (J, CH, HS), 7 (C, K, G), 8 (F, v, pH), 9 (p, b), 10 (Z, S).

The work of Hérigone also contains many mathematical terms used since: Parallelipipedum (for Parallelepiped ).

The Darkroom of Hérigone

In its Course mathematicus (Chapter 6, page 113), Hérigone describes a Darkroom having the form of a cut without more precision, but Johann Zahn was to take up this idea in its Oculus Artificialis Teledioptricus Sive Telescopium (1685). The darkroom of Hérigone was more one curiosity that another thing, supposed to make it possible its user to supervise other guests at the time same as itself drank. The inclined mirror with 45° of this apparatus was provided with a stylized diaphragm, while the container itself consisted of a cup of glass through which the image was seen.

Expert

Hérigone took part at several scientific commissions before the hour, with which one, including/understanding Etienne Pascal and Claude Mydorge, was charged to evaluate the effectiveness of a method suggested by Jean-Baptiste Morin to find the Longitude according to the apparent movement of the Moon.

One named a crater of the the Moon Herigonius in his homage.

Sources

Michel Chasles - Historic insight on the development of the methods in geometry (1837), libr. Hayez, Brussels
Emile Fourrey - geometrical Curiosities (1907), libr. Vuibert, Paris

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