NICERON, JOHN FRANCIS, a French philosopher, was born at Paris in 1613. Having finished his academic studies, with a success which raised the greatest hopes of him, he entered into the order of the Minims, and took the habit in 1632; and, as is usual, he changed the names given him at his baptism for that of Francis, the name of his paternal uncle, who was also a Minim, or Franciscan. The inclination and taste which he had for mathematics appeared early. He began to apply himself to that science in his philosophical studies, and devoted to it all the time he could spare from his other employments, after he had completed his studies in theology. All the branches of the mathematics, however, did not equally engage his attention; he confined himself particularly to optics, and only learned of the rest as much as was necessary for rendering him perfect in this. There remain still, in several houses wherein he dwelt, especially at Paris, some excellent performances, which discover his skill in this way, and which make us regret that a longer life did not suffer him to carry it to that perfection which he desired; since one cannot help being surprised that he proceeded so far as he did, in the midst of those occupations and travels by which he was forced from it during the short space of time which he lived. He hath himself observed in the preface to his Thaumaturgus Opticus, that he went twice to Rome; and that, on his return home, he was appointed teacher of theology. He was afterwards chosen to accompany Father Francis de la Noue, vicar general of the order, in his visitation of the convents throughout all France. But the eagerness of