Italian Math manuscript. GALILEIANA. CLAVIUS. Osservationi aritmetiche scelte dalla practica del P. Clavio.

GALILEIAN. CLAVIUS, Christophorus. Selected arithmetical observances from the practica of Fr. Clavius. Manuscript, c. 1580-90. 8vo oblong, 98 x 143 mm. Coeval vellum binding. Altogether 90 folios of text. Pages numbered to 169, 1 unnumbered. The next 5 papers are unnumbered. Text on one 11-line column, crisp lowercase cursive handwriting, numerous equations and diagrams drawn in the text. Watermark: Angel within circle with halo, letters AR below circle. Watermark similar to Briquet 675, Pisa 1569. Good state of preservation. Important mathematical manuscript setting out in detail and concisely the mathematical theory of Christopher Clavius. The German Jesuit mathematician and astronomer taught courses dealing with this subject within the Jesuit order in Rome and published his Prattica Aritmetica in 1586. The author of this manuscript brilliantly summarizes the contents of this work. The order in which these 'Arithmetical Observations' are set out and the explanations with more accessible examples than those offered by Clavius, suggest that this is a manual created specifically for teaching purposes. At the end, on paper 90 recto, the title "Rules for Extracting Some Roots First Article. Dell'estrattione della radice cuba. The members are distinguished. Each member beginning with the right side. "This title directly recalls the Rules elaborated by Galileo Galilei, found in some of his manuscripts. Some considerations: - at the end of the manuscript there is the expression "cube root." Clavius always writes "cubic root," while Galileo, both in his 'Defense against calumnies and impostures' of 1697 and in his work on the Compasses, uses "cubic root." - Galileo prepared handwritten manuals, for example for the use of his Compasses, which he then handed over to his students, as he explicitly states in the 'Defense against calumnies and impostures; - finally, the handwriting turns out to be very similar to that found in the notes to Petrarch's Rime, although in that case the writing is more rapid and informal, while in this manuscript it is neat and regular, which supports the hypothesis that this is a manual to be given to a pupil. Upon request, we have a more detailed sheet of the manuscript.The lot is sold with a certificate of free circulation. - Antonio Clericuzio, 3 Galileo Galilei, in Umberto Eco, Riccardo Fedriga, La filosofia e le sue storie: The Modern Age, Laterza, 2015.- Giuseppe Nolè, Galilean Aristotelianism in Early Writings, 12/20/2009, in: https://mondodomani.org/dialegesthai/articoli/giuseppe-nole-02- William A. Wallace, I. Galileo's Early Period (1564-1610) - II. Galileo and Copernicanism (1611-1632) - III. Galileo's trial and final years at Arcetri (1633-1642) - IV. The revision of the Galileo case.https://disf.org/Galileo-Galilei- Stefano Salvia, three essays on the young Galileihttps://www.academia.edu/4398310/Il_laboratorio_del_giovane_Galileo_Alle_origini_della_fisica_modern GALILEAN. CLAVIUS, Christophorus. Arithmetic observations selected from the practica of Fr. Clavius, [Arithmetic observations selected from the practice of P. Clavius]Manuscript, ca. 1580-90. 8vo oblong, 98 x 143 mm. Contemporary parchment binding. A total of 90 sheets of text. Pages numbered to 169, 1 unnumbered. The next 5 leaves are unnumbered. Text in one column of 11 lines, neat handwriting in lowercase Italic, numerous equations and diagrams drawn in the text.Watermark: Angel within a circle with halo, letters AR below the circle. Watermark similar to Briquet 675, Pisa 1569. Specimen in good condition. Important mathematical manuscript that explains Christopher Clavius' mathematical theory in a detailed and concise manner. The German Jesuit mathematician and astronomer taught courses dealing with these subjects within the Jesuit order of Rome and published his Practica Arithmetica in 1586. The author of this manuscript brilliantly summarizes the content of this work. The order in which these 'Arithmetic Observations' are exposed and the explanations with more accessible examples than those proposed by Clavius, suggest that it is a manual created specifically for teaching.At the end, on page 90 recto, the title "Rules for extracting some roots Article primo. Dell'estrattione della radice cuba. The members are distinguished. Each member beginning on the right side" [Rules for extracting some roots First article. Of the extraction of the Cuban root. Members stand out. Each member starting from the right side]. This title directly recalls the Rules developed by Galileo Galilei, found in some of his manuscripts. Some considerations: - at the end of the manuscript there is the expression "radice cuba." Clavius always writes "radice cubica," while Galileo, both in the 'Defense against calumnies and impostures' ['Defense against calumnies a