For the germs of many mystic beliefs regarding number and the like, which were incorporated into mediaeval theology, see Zeller, Plato and the Older Academy, English translation, pp.

254 and 572, and elsewhere.

As to the connection of spiritual things with inorganic nature in relation to chemistry, see Eicken, p.634.On the injury to science wrought by Platonism acting through mediaeval theology, see Hoefer, Histoire de la Chimie, vol.i, p.90.As to the influence of mysticism upon strong men in science, see Hoefer; also Kopp, Geschichte der Alchemie, vol.i, p.
211.

For a very curious Catholic treatise on sacred numbers, see the Abbe Auber, Symbolisme Religieux, Paris, 1870; also Detzel, Christliche Ikonographie, pp.

44 et seq.; and for an equally important Protestant work, see Samuell, Seven the Sacred number, London 1887.