"Fog-bow among the mountains."  From The Dew-Drop and the Mist by Charles Tomlinson, 1847.

"In memory of a day when the west wind and the rainbow met."  From the dedication in Keynotes by George Egerton, 1893.

May rainbows lead you to the spooky castles of life, if that's your journey.  From Lustige Blätter, 1908.

"Rainbow seen from plane is circle of color."  From Popular Mechanics, 1934.

How nifty: the eras of history and characters of empires understood as colors of a rainbow.  From The Western Monthly Magazine and Literary Journal, 1836.

"The Ulloa Circle."  From Popular Mechanics, 1925.

Here's a rainbow of soldiers, courtesy of Cartoons Magazine, 1917.

"Fountain of Youth" Florida Water, from c. 1890.

From an ad for Buckingham's Dye for the Whiskers, c. 1890.

Before the "horse of many colors" in Oz, there was the rainbow horse of folklore that "delivered souls through the cosmos, avoiding wayward angels" (Max Evans, Animal Stories).

From c. 1890.

The colors of "any reasonable rainbow" include "white for inside and outside."  From c. 1890.

From Prof. Oddfellow's sketchbook:

"A rainbow spans the horizon for as long as your heart needs to reconcile itself to life." —Michel Tournier (as quoted in A Thousand Plateaus by Deleuze & Guattari).

From Carolina Magazine, 1921.  (We previously discovered another precursor to If You're Afraid of the Dark, Remember the Night Rainbow, which we showcased here.)

Here's an unusual appearance of the Aurora Borealis, as obvserved by Captain Parry in his expedition to the Arctic regions, from the Encyclopedia of Natural and Artificial Wonders and Curiosities by John Platts, 1876.  (We previously discovered other precursors to If You're Afraid of the Dark, Remember the Night Rainbow, which we showcased here and also here.)

From L'Arche de Noé by Paul Guigou and Auguste Vimar, 1909.

Here's a precursor to posing with a raindbow, from Ethica Naturalis by Johann Christoph Weigel, 1700.