On the Origin of Clockwork, Perpetual Motion Devices, and the Compass Part 5

[29] Sotheby and Co., London, sale of March 14, 1957, lot 154.

The outer rim of the rete has 120 teeth.

[30] The Latin text of the treatise on the Albion, has been transcribed by Rev. H. Salter and published in R. T. Gunther, _Early science in Oxford_, Oxford, 1923, vol. 2, pp. 349-370.

An a.n.a.lysis of its design is given in Price, _op. cit._ (footnote 22), pp. 127-130.

[31] Such evidence as there is for the existence and form of the clock is collected by Gunther, _op. cit._ (footnote 30), p.

49.

[32] I have discussed this new ma.n.u.script source in "Two medieval texts on astronomical clocks," _Antiquarian Horology_, 1956, vol. 1, no. 10, p. 156. The ma.n.u.script in question is ms.

230/116, Gonville and Caius College, Cambridge, folios 11?-14? = pp. 31-36.

[33] _The Chronicle of Jocelin of Brakelond_ ..., H. E. Butler (ed.), London, 1949, p. 106.

[34] C. B. Drover, "A medieval monastic water-clock,"

_Antiquarian Horology_, 1954, vol. 1, no. 5, pp. 54-58, 63.

Because this water clock uses wheels and strikes bells one must reject the evidence of literary reference, such as by Dante, from which the mention of wheels and bells have been taken as positive proof of the existence of mechanical clocks with mechanical escapements. The to-and-fro motion of the mechanical clock escapement is quite an impressive feature, but there seems to be no literary reference to it before the time of de Dondi.

[35] _Annales de la Societe Royale d'Archeologie de Bruxelles_, 1896, vol. 1/8, pp. 203-215, 404-451. The translation here is cited from Drover, _op. cit._, (footnote 34), p. 56.

[36] L. Thorndike, _The sphere of Sacrobosco and its commentators_, Chicago, 1949, pp. 180, 230.

[37] The alb.u.m was published with facsimiles by J. B. A.

La.s.sus, 1858. An English edition with facsimiles of 33 of the 41 folios was published by Rev. Robert Willis, Oxford, 1859. An extensive summary of this section is given, with ill.u.s.trations, by J. Drummond Robertson, _The evolution of clockwork_, London, 1931, pp. 11-15.

[38] M. Jules Quicherat, _Revue Archeologique_, 1849, vol. 6.

[39] M. C. Fremont. _Origine de l'horloge a poids_, Paris, 1915.

[40] For this, I have used and quoted from the very beautiful edition in English, prepared by Silva.n.u.s P. Thompson, London, Chiswick Press, 1902.

[41] See E. G. R. Taylor, "The South-pointing needle," _Imago Mundi_, Leiden, 1951, vol. 8, pp. 1-7 (especially pp. 1, 2).

[42] 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 subst.i.tute for bell-ringing on Good Friday. Unfortunately I can find no evidence for or against the conjecture.

[43] W. E. May, "Alexander Neckham and the pivoted compa.s.s needle," _Journal of the Inst.i.tute of Navigation_, 1955, vol.

8, no. 3, pp. 283-284.

[44] W. E. May, "Hugues de Berze and the mariner's compa.s.s,"

_The Mariner's Mirror_, 1953, vol. 39, no. 2, pp. 103-106.

[45] H. Balmer, _Beitrage zur Geschichte der Erkenntnis des Erdmagnetismus_, Aarau, 1956, p. 52.

[46] The collection is the _Gami 'al Hikajat_; the relevant pa.s.sage being given in German translation in Balmer. _op. cit._ (footnote 45), p. 54.

[47] Balmer, op. _cit._ (footnote 45), p. 53.