Who invented the kaleidoscope? Explore Sir David Brewster's original 1817 patent, the early copies in London and Paris, and his defense of the optical wonder.

A short history of mirrors: polished metal, Venetian tin-mercury glass, chemical silvering, vacuum aluminium and the front-surface mirror in kaleidoscopes.

What annular and parallel kaleidoscopes are, how Dollond and Ruthven built them in Brewster's 1819 treatise, and how two mirrors make a straight band.

Why a kaleidoscope image looks uneven when the eye is off position, and Brewster's 1819 rule for placing the eye at the junction of the mirrors.

Who Charles G. Bush was, what his 1873-1874 US kaleidoscope patents claim, and how his sealed liquid-filled glass ampules work in the object cell.

How Brewster proposed in 1819 to project kaleidoscope patterns with a lantern, a solar microscope and a camera obscura, and the limits he found.

How kaleidoscope collectors assess an instrument, what the Brewster Kaleidoscope Society does, and how to start and document a collection.

Porta, Kircher and Bradley joined two plane mirrors long before 1817. What each device did, and why Brewster argued none of them was a kaleidoscope.

Brewster's 1819 Treatise describes kaleidoscopes 1 to 1.5 inches long, used as an ornament. What the chapter says and the optics behind it.

Brewster's 1819 estimate: 200,000 kaleidoscopes sold in London and Paris in three months - and why he judged most of them optically incorrect.

A chapter-by-chapter guide to Sir David Brewster's book on the kaleidoscope: mirror angles, object cell, telescopic kaleidoscope, designs and uses.

What goes in a kaleidoscope object cell: Brewster's rules for object shape, transparency, colour, fill level and motion, and the cell formats in use today.

What Sir David Brewster wrote about using the kaleidoscope for architectural ornament, ornamental painting, carpet design and photographic recording.

Polyangular, annular, parallel, polycentral, solid-glass, projection, polarized-light, stereoscopic and microscopic kaleidoscopes, as Brewster built them.

Chapter X of Brewster's 1858 book describes a kaleidoscope with a lens for distant objects. What he specified, and how it relates to the teleidoscope.

Who invented the kaleidoscope and when: David Brewster's 1817 patent, the 1818 craze, Charles Bush's parlour instruments, the 20th-century revival and what changed.

Rocco (Roi) Ramon's letter to members of the Brewster Kaleidoscope Society, published in News Scope, Spring 2026: brass, structure and the object chamber.