11558
[Commentary:
The reference to Pappus is to Commandino's edition of Books III to Mathematicae collectiones
(Pappus . The relevant proposition on page 44 is Proposition IV.11. Harriot's diagram is the same as the one given by Commandino except for his use of lower case letters.
Theorema XI. Propositio XI.
Sit semicirculus ABC, & inflectatur CBA. ducaturque CD ita, vt CB fit æqualis utrisque simul AB & perpendiculares BE EF ducantur. Dico AF ipsius BE duplæ
Let there be a semicircle ABC, curved along CBA. The line CD is drawn so that CB is equal to AB and CD together, and there are drawn the perpendiculars BE and EF. I say that AF is twice BE.]
Theorema XI. Propositio XI.
Sit semicirculus ABC, & inflectatur CBA. ducaturque CD ita, vt CB fit æqualis utrisque simul AB & perpendiculares BE EF ducantur. Dico AF ipsius BE duplæ
Let there be a semicircle ABC, curved along CBA. The line CD is drawn so that CB is equal to AB and CD together, and there are drawn the perpendiculars BE and EF. I say that AF is twice BE.]
Utile ad
[Translation: Useful for ]
[Translation: Useful for ]
et ad locum
de
[Translation: and for the place of ]
de
[Translation: and for the place of ]
pappus pag.
[Translation: Pappus, page ]
[Translation: Pappus, page ]