**Cristoforo Alasia**'s father was the noble Lieutenant Francesco Alasia-Aluffi from Felizzano in Piemonte, the son of Vincenzo Alasia and Celestina Aluffi. Francesco married Giovanna Francesca de Quesada (1842-1922) from Sassari-Sardegna, daughter of Cristoforo and Speranza Cugia Paliacio on 28 January 1864. Vincenzo and Giovanna had three sons, Cristoforo (the subject of this biography), Tommaso, who became a magistrate, and Enrico, born 1866, who became a doctor.

Let us note that there are problems with Cristoforo Alasia's year of birth. Almost all biographies give 1869 as the year of his birth, but his baptismal certificate gives 1864. The date 1864 is also more consistent with his undergraduate university career. The source of the 1869 date appears to be George Halsted [3]. Halsted wrote his article during Alasia's lifetime and indeed had corresponded with Alasia before writing the article. If, as we believe, the 1864 date is correct, we suggest the error occurred by Halsted misreading Alasia's handwriting. However, we have not been able to make a definite decision about which date is in error.

Cristoforo Alasia studied at the universities of Cagliari, Turin and Rome. The name "Alasia Cristoforo", appears in the yearbook of the University of Turin as matriculated in the first year of the course for the Diploma in Mathematical, Physical and Natural Sciences in the academic year 1883-1884. In Turin he was a pupil of Enrico D'Ovidio and Giuseppe Peano, while at the Polytechnic School of Engineering in Rome he studied with Luigi Cremona and Valentino Cerruti (1850-1909). There he took Cerruti's famous course on rational mechanics. In 1891 he published the 160-page work *Elementi della teoria generale delle equazioni ed in particolare delle equazioni di terzo e quarto grado e delle equazioni indeterminate* .

Due to his father's sudden death he had to return to Sardinia and dedicate himself to teaching. In 1893 he was appointed as a teacher of mathematics and natural sciences at the Gymnasium in his home town of Sassari, having won this position in a competition. Later, he taught at the Royal High School of Tempio Pausania, at the Royal High Schools of Oristano and of Ozieri in Sardinia, at Brindisi in Puglia, and finally at the Royal High School of Albegna, Liguria. He married Maria Vittoria Guglielmo of Tempio Pausania; they had two daughters, Caterina (known as Tina) and Giannetta.

Throughout his life he remained in contact with the mathematical community of the time, in particular with his teachers and with Henri Poincaré. Despite being a school teacher, he was the author of around 150 publications that presented his research on a variety of subjects such as astronomy, geometry, rational mechanics, history of mathematics etc. that gave him a high reputation both nationally and internationally. Perhaps his most famous work was his paper on the geometry of the triangle *La recente geometria del triangolo* (1900).

His surname is linked to the theory of Alasia and, in particular, with being the founder and the first editor of the magazine *Le Matematiche Pure ed Applicate, Periodico mensile di matematiche pure ed applicate, superiori ed elementari, ad uso dell'istruzione media e superiore* , to which important mathematicians such as Charles Hermite contributed. This journal was first published in February 1901 with Scipione Lapi as its editor. Lapi was an excellent choice since he had a high reputation for his abilities. The journal was typeset in Città di Castello in Umbria. Alasia was pleased with the initial response to his journal and he wrote to Ernesto Cesàro on 22 November 1900:-

He gives a list of twenty-four names which includes Paul Appell, Henri Brocard, Cesare Burali-Forti, Ernesto Cesàro, George Halsted, Émile Lemoine, Giuseppe Peano, Mario Pieri, and Henri Poincaré.... We are interested that a short list of collaborators, whose names are ones of the most distinguished scientists, give a clear sign of the scientific value of the periodical. Some have already joined and volunteered communications ...

The first volume not only contains a paper by Charles Hermite, but also an obituary of Hermite since he died in 1901. This obituary was translated into English by George Halsted and published in the *American Mathematical Monthly*. As well as papers, the journal contained reports of work published in other journals, reviews of books, some reviews by Alasia himself, and problems with solutions to them given in a later part.

George Bruce Halsted published the article "Cristoforo Alasia" in the *American Mathematical Monthly* in 1902 (see [3]). Halsted writes:-

Alasia returned the compliment with an appreciation of Halsted on the occasion of his appointment as President of the Mathematics and Astronomy Section of the American Society for the Advancement of Science. Alasia's 5-page article "George Bruce Halsted" came with a portrait and appeared in the second volume ofWhen a new star comes out in the skies, thither turns the observing eye. "Le Matematiche" is a new luminary among scientific periodicals, though sailing safely now far into its second year. Its director, its creator, Professor Alasia, has won the confidence and is attracting the attention of the mathematical world. ... The monthly journal of pure and applied mathematics founded by Professor Alasia, "Le Matematiche," has had an extraordinary success. The last thing ever written by the great Hermite was for it. Professor Alasia has been able to win the support and friendship of many of the most illustrious of living mathematicians, for example, Poincaré.

*Le Matematiche Pure ed Applicate*.

Initially parts of the journal were published rapidly. The first part of the first volume appeared in February 1901, the second part in March and the third in April. However, in the first part of the 1903 volume which was published in January of that year, Alasia announced a temporary halt to publications because of excessive commitments of the typesetter who was working on publishing the proceedings of the Third International Congress of Historical Sciences, which took place in Rome in the first week of April 1903. In fact the publisher died in September 1903 and publication of *Le Matematiche Pure ed Applicate* never resumed.

Halsted writes in [3] in the year 1902:-

In 1911 he received a gold medal from the Royal Irish Academy of Dublin for a work in astronomy. The medal was awarded for a memoir by Alasia on the determination of the parabolic orbit of a comet published inHis love of science did not however prevent him from also occupying himself with the fine arts; he has won two prizes at expositions of dilettanti in painting. Professor Alasia is a gifted linguist. He has an elegant Italian style, writes the purest French, and at present is engaged with Professor Dionisio Gambioli in translating into Italian Cajori's 'History of Physics'. They will enlarge the work by two additional chapters and copious notes. It is expected to appear at the end of this year. In his Essay on the nomenclature(bibliographic)of the New Geometry of the triangle, our author proposes to give the most complete possible list of the terms which have entered the domain of geometry in these latter years, to give their veritable signification, to investigate what geometer has first used them, upon what occasion, etc. In addition, when it is a question of a point or a straight, he has given its representation according to the method of Grassmann; and for circles and conics he has given the equation in barycentric or normal coordinates. His is a charming figure in the new renaissance of creative productivity in Italy. His fine judgment and powers of assimilation are illustrated in his 'Poligeometrognomia generale e la Geometria Non-Euclidea del Chrystal', a translation of Chrystal's 'Non-Euclidean Geometry', preceded by a general resume, historic and bibliographic, in exposition of the foundations of geometry, remarkable in erudition and breadth of insight.

*L'amateur*(Milan, 1906), 259-264.

In his article [3] Halsted exhibits Alasia's "splendid fertility" by giving a list of his other writings additional to those mentioned in his article.

Here is Halsted's list with items from our list removed:-

- Elementi della Teoria delle equagioni, ecc. - Napoli, 1893, B. Pellermo, ed.
- Sulla deviazione dei gravi, - lettera alla Societa Astronomica d'Francia.
- Su di alcune proprietà dei numeri e delle congruenze, ecc. Civitanova - Marche, 1898. C'est le vol. VI, sect. Science, de la Collection d'Audes italiane qui a été publiée par l'éditeur D. Natalucei.
- Su di alcune proprietà delle linee geodetiche, - Sassari, 1898.
- 566 Relazioni metriche e trigonometriche fra gli elementi d'un triangolo piano, -ibid. 1900.
- Su di alcuni teoremi di Le Paige e Deruits, Madrid, 1899.
- Producto de una serie cualqueira por la exponencial
*e*^{-x}. (Estrait du Progreso Matemático de Zaragoza, ser. 2'. An. II, no. 10, 1900). - Une méthode élémentaire de recherche del maxima et minima. (Extr. de la Gazeta Matematica. An. VII, no. 9, Mai 1902, Buçuresti, - (Rumania).
- Alcune asservazioni sui pendoli e sui cronometri (Extr. de la Rassegua Tecnica Italiana, An. II, ni. 4e5, Messina, 1902).
- Elementi di Trigonometria Piana e Sferica, traduction, avec notej et adjointes du Traité de M. l'Abbe H. Gelin, de Huy.
- Trattáto d Aritmetica, en collaboration de M. Gelin, à Huy.
- Alcune formule della Teoria delle Superficie (Extr. de la Revista simestral de Matemática, An. II, no. 6, Zaragoza, 1902).

**Article by:** *J J O'Connor* and *E F Robertson*