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These long chains of perfectly simple and easy reasonings by means of which geometers are accustomed to carry out their most difficult demonstrations had led me to fancy that everything that can fall under human knowledge forms a similar sequence; and that so long as we avoid accepting as true what is not so, and always preserve the right order of deduction of one thing from another, there can be nothing too remote to be reached in the end, or too well hidden to be discovered.
Discours de la Methode. 1637.
Leonard Digges' Tectonicon
This is the title page of the Tectonicon by Leonard Digges (1520-1559), a 1634 edition of the work originally published in 1556. Digges was an English astronomer, mathematician, and instrument maker, credited with the invention of the reflecting telescope and the theodolite. His book discusses methods of measurement.
At the beginning of the book, Digges discusses basic ideas of arithmetic, preliminary to dealing with measurement.
On page 4, basic ideas of measurement are discussed.
And on page 5, we have definitions of various parts of the circle.