On shadow clocks

I believe I have made it sufficiently clear in the first chapters of this book that men living in the subarctic region have continuous daylight for six months, and as many months of darkness. ¹ Nevertheless I think that from this point onwards I shall be bound to meet the astonishment of many readers at the clever inventions with which they apportion their times for rest and work by distinguishing between days, nights, and hours. You must know therefore that the inhabitants of the extreme North, who live beyond a latitude of 86°, ² have no use for a sundial such as Anaximenes of Miletus is said (for example by Pliny) to have discovered when he was in Sparta, ³ nor for any other clock, whether constructed with weights, wheels, water, or a scale of spaced lines. They use only the very high and low points of rocks, arranged partly by Nature, partly by human skill, and by their shadows cast from the sun’s rays these give unerring guidance, so that people can distinguish one section of a day from another; in winter both by day and night, even though the moon is not shining, their experience enables them to gauge the sequence of time very accurately through the voices and behaviour of birds and land animals, of which there is an infinite abundance there. ⁴ So they are satisfied with such signs as pointed rocks or clues from wild animals. The means of navigation used by those who dwell on the shores of the Ice Sea or the Scythian Sea when they are sailing beneath the Arctic Pole I shall describe elsewhere, as also the work of those who toil by the light of the moon. ⁵ But what I said above, about the way in which men who live under the Pole recognize and distinguish the hours of the day by the calls and behaviour of wild animals, is nothing wonderful, since Nature prompts both domestic and wild creatures to observe times in order of succession, as is evident to folk with experience. The practice of partitioning days, however, derives originally, we believe, from Hermes Trismegistus, who divided up the day and hours by an Egyptian animal’s urinating twice six times. ⁶ People say that the wild ass gives a similar indication; on 25 March it brays at frequent intervals, twelve times in the day and as often during the night, as a sign that it is then the equinox. ⁷

Where daylight last for six months

Sundial

Anaximenes

Points of cliffs used for clocks

Numberless birds Wild creatures indicate the hours

Hermes Trismegistus

Hour shown by urinating Equinox is indicated by braying of wild ass