Part 9

M. Jules Quicherat, Revue Archèologique, 1849, vol. 6.

M. C. Frémont. Origine de l'horloge à poids, Paris, 1915.

For this, I have used and quoted from the very beautiful edition in English, prepared by Silvanus P. Thompson, London, Chiswick Press, 1902.

See E. G. R. Taylor, "The South-pointing needle," Imago Mundi, Leiden, 1951, vol. 8, pp. 1-7 (especially pp. 1, 2).

I have wondered whether the medieval interest in perpetual motion could be connected with the use of the "Wheel of Fortune" in churches as a substitute for bell-ringing on Good Friday. Unfortunately I can find no evidence for or against the conjecture.

W. E. May, "Alexander Neckham and the pivoted compass needle," Journal of the Institute of Navigation, 1955, vol. 8, no. 3, pp. 283-284.

W. E. May, "Hugues de Berze and the mariner's compass," The Mariner's Mirror, 1953, vol. 39, no. 2, pp. 103-106.

H. Balmer, Beiträge zur Geschichte der Erkenntnis des Erdmagnetismus, Aarau, 1956, p. 52.

The collection is the Gami 'al Hikajat; the relevant passage being given in German translation in Balmer. op. cit. (footnote 45), p. 54.

Balmer, op. cit. (footnote 45), p. 53.

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