Note 503 — Chapter XI · THE LOGARITHMIC SPIRAL

See, on the math­e­mat­i­cal history of the Gnomon, Heath’s Euclid, I, passim, 1908; Zeuthen, Theorème de Pythagore, Genève, 1904; also a curious and interesting book, Das Theorem des Pythagoras, by Dr. H. A. Naber, Haarlem, 1908.