Erasmus Darwin's visual experiments

This image is from Erasmus Darwin's book "Zoonomia" (an edition from 1800). In the first part of the book, the grandfather of Charles Darwin explains some characteristics of the human visual system, and suggest several experiments to the reader. The figures are hand coloured.

Explaining the rainbow

In his 1888 book "L'atmosphère. Météorologie populaire", Camille Flammarion used this beautiful engraving to explain the formation of the rainbow.

Haeckel's sketch of human migrations

In 1868 Ernst Haeckel published The history of Creation (originally in German). The book included this interesting map, showing the migration of human "races" from a monophyletic origin somewhere in the... "Paradise?". This is a picture of the French edition from 1874. The title of the plate is :"A hypothetical sketch of the origin and distribution throughout the Earth of the twelve races of Man from Lemuria".

Rømer's demonstration that light has a finite speed

As early as in 1676, the Danish astronomer Ole Rømer proposed an experiment to measure the time light takes in propagate from the Sun to the Earth. In 1738 Voltaire published The Elements of Sir Isaac Newton's Philosophy; in that book Voltaire provides this beautiful illustration of Rømer's demonstration. The conclusion was that "light employs seven or eight minutes in its passage from the Sun to the Earth".

Ontogenetic tree from 1844

This diagram showing the common and divergent development of different animals appeared in 1844's Vestiges of the Natural History of Creation, way before Darwin's evolutionary tree. The book, written by Robert Chambers, was initially published anonymously.

The Origin of Species only figure

This is the only figure that appeared in Charles Darwin's The Origin of Species. Photograph from an original copy of the sixth edition (the definitive one).

Man's place in Nature

Frontispiece of the first edition of the book "Evidence as to Man's place in Nature", by T. H. Huxley, 1863.