As to Mathematics in education, it is evident that a similar process of development must have been the history of this branch, with the limitation however, that mathematical science has not been so nearly created anew within these last centuries, as some other departments. Father Christopher Clavius, "the Euclid of his time," was engaged by Gregory XIII in reforming the Calendar, the same which we use to-day; he died in 1612. His death intervening, while his complete works were being republished, Father Ziegler superintended the new edition, till it was finished in five tomes. Francis Coster, at Cologne, Hurtado Perez, at Ingolstadt, Henry Garnet, an Englishman, and Grienberger, successor of Clavius, both at Rome, belonged, with other mathematicans of the Order, to the sixteenth century. The writers of the preliminary _Ratio_, 1586, require that, in a brief course of Mathematics, "Euclid's Elements" "be seasoned always with some application to Geography or the Sphere"; then, in the following year, the rest of Father Clavius' "Epitome of Practical Arithmetic"[173] is to be finished;[174] and special courses are provided for members of the Order, who give promise of eminence.[175] Indeed, whether as Professors of officers for the army and navy, or as constructing and directing observatories, the members pursued every branch of Mathematics, pure and applied. Father L'Hoste's "Treatise on Naval Evolutions" was used in the French navy, as "the Book of the Jesuit."[176] Of this book the Count de Maistre writes quaintly in 1820: "An English Admiral assured me less than ten years ago, that he had received his first instructions in the 'Book of the Jesuit.' If events are taken for results, there is not a better book in the world!"[177] Eximeno, at the school of Segovia, instructed young nobles in Mathematics and the science of Artillery. And so, in general, courses were provided, according as the needs of respective localities required. The Republic of Venice struck a gold medal in honor of Vincent Riccolati, the Jesuit engineer, just as the King of Denmark honors De Vico, the astronomer, with a gold medal struck in his honor, and having the words inscribed, "Comet Seen, Jan. 24, 1846."[178] Kircher, Boscovich, Pianciani, Secchi, Perry, honored with the fellowship of so many learned and scientific Academies, and exercising a distinct influence to-day, either by the far-reaching effects of their researches, or by their actual contact with science, may be looked upon as belonging to our most recent times.[179]