Public domain

A photomicrograph of a Mare's Tail stem by <n>Arthur E. Smith</n> from the 1909 book <n>Nature Through Microscope and Camera</n>.

Plate 92, an illustration of diatoms from <n>Adolf Schmidt</n>'s <n>Atlas der Diatomaceenkunde</n>, ca. 1890.

A photograph by <n>Harry Whittier Frees</n> from the 1911 children's book <n>Kittens and Cats: A First Reader</n>.

A vintage scientific diagram of <n>Radium</n>, from a plate labeled TAB. XV.

A photograph from the series <n>Art Forms in Nature</n> (1928) by photographer <n>Karl Blossfeldt</n>.

Plate XVI from <n>Thomas Wright</n>'s 1750 book, <n>An Original Theory or New Hypothesis of the Universe</n>.