Catalan Atlas, 14th century
Catalan Atlas, 14th century. The 6-page Catalan Atlas (1375) was produced on vellum by the Jewish cartographer Abraham Cresques. It was commissioned by the rulers of the Kingdom of Aragon (north-eastern Spain). Two pages are on cosmography, and four on geography. This page shows the five known planets (plus the Moon and Sun) orbiting the Earth, the zodiac, moon phases, calendars, and the four seasons. The text is in Catalan. This version is a facsimile (exact reproduction) produced in 1959 by the Spanish scholars Joan Vernet and David Romano. The facsimile pages have been illuminated by hand in colour and gold leaf.
© LIBRARY OF CONGRESS/SCIENCE PHOTO LIBRARY
Snowflake. This is an ice crystal that forms in air that has a temperature near the freezing point of water. If the air is calm, then a symmetrical, hexagonal snowflake can form. The two main growth patterns observed are faceting and branching. When growth is fast and unstable, branching patterns create a dendritic snowflake. Slower growth allows the straight lines and hexagonal shapes of a plate snowflake. This snowflake displays both types of growth. The type of growth also depends on temperature, which changes in a different way for each snowflake, causing the wide variation in snowflake patterns.
© Kenneth Libbrecht/Science Photo Library
Mistletoe. Leaves and berries on sprigs of the European mistletoe (Viscum album). Mistletoe is a parasitic, evergreen shrub that can grow on a variety of trees, but is usually found on apple trees. The translucent white berries appear from September to January and contain a sticky pulp, which surrounds the seeds.
© LAWRENCE LAWRY/SCIENCE PHOTO LIBRARY