Treatise on astronomy
John Herschel's Treatise on Astronomy, published in London by Longman in 1833 as a volume of Lardner's Cabinet Cyclopaedia, explaining planetary motion to general readers and students. The 60 wood-engraved figures are bare line diagrams: ellipses with dashed circles, orbits swept into lettered sectors from a central sun, nested rings, tangents and sight-lines to a planet's disc, all letter-keyed in italic and roman capitals.
