'Eclipses' and 'The Theory of the Tides', c 1851.
© Science Museum / Science & Society Picture Library
Astronomical diagrams drawn and engraved by John Emslie, showing how eclipses take place, and how tides are caused by the influence of the gravity of the Sun and the Moon upon the Earth's seas and oceans. Both lunar and solar eclipses are illustrated, as are the alignments of the Sun and Moon relative to the Earth that give rise to neap and spring tides. Published by James Reynolds (174 Strand, London).