THE FULLNESS OF TIME

A celebration of circadian rhythms.

British curator, artist, and educator Haynes, who has served as timekeeper in residence at University College London’s Petrie Museum, makes an engaging book debut with a naturalist’s view of marking time. Ranging widely around England, Scotland, and Iceland, Haynes becomes newly attentive to the ways plants and animals respond to changes in light and seasons. She listens to layers of song that build as birds join the dawn chorus, and to the sounds of owls and bats at night. She notices the regular unfolding of flowers—the primrose in the evening, and many flowers, including the daisy, at predictable times during the day. Linnaeus and other scientists tried to create floral clocks based on the movement of petals, most recently at the Botanical Garden in Bern, Switzerland. The Cambridge University Botanic Garden Circadian Beds are planted with flowers that give off scents, half in the morning, half in the evening, possibly an adaptation for attracting pollinators. Sundials have served as rudimentary clocks since ancient times: a stick in the turf or a spike stuck into a wall with lines scratched beneath could suffice to mark time by the movement of shadows. Humans contrived ways both to ascertain time and keep time: In northern Scotland, Haynes hears songs and chants sung by weavers, millers, and knitters to accompany their work. Assuming that sunlight was of primary importance in telling time, Haynes is surprised to discover the colors and qualities of twilight, which have given rise to three gradations: civil twilight, when it is too dim to read and the brightest stars emerge; nautical twilight, when the atmosphere is too dark to see the horizon; and astronomical twilight, when the faintest stars appear.

Curiosity and enthusiasm impel a foray into the natural world.