The best reason to reopen an old book is the thing you can't believe is in it. These are the entries that made us stop and read them aloud to whoever was nearby.
The 1920 Encyclopaedia of Occultism records that the word, 'formed from the letters of the abraxas,' was written in a diminishing triangle and used by Serenus Sammonicus as a spell against asthma — 'equally efficacious either way' according to Julius Africanus.
Aiton's Encyclopedia filed powered flight under the airship — in 1910 the dirigible still looked like the future, and the aeroplane like a novelty. The entire entry is three words long.
The radium entry notes the element is 'seldom prepared, as it is too expensive,' and marvels at rays 'of three sorts.' Marie Curie — one Nobel Prize in by then, a second on the way — appears as 'and wife.'
The encyclopedia traces the motor car to Roger Bacon's 13th-century prediction, and to a 1641 book by Solomon de Coste of Normandy — the horseless carriage as a 700-year-old idea that finally shipped.
Aiton's entry on appendicitis explains the vermiform appendix was 'at one time useful to man' — a body part politely retired, like a telegraph office.
The sailor's name for the bottom of the sea sits in the 1891 Nautical Encyclopedia as sober working vocabulary, alongside Dead Lights, Dead Water and Dead Wind — the sea's whole gothic glossary, catalogued without a wink.
Under Strange Occurrence, the dictionary offers: 'If this were played upon a stage now, I could condemn it as an improbable fiction.' There is a filed quotation for every situation you will ever be in.
Vulcan was a real nineteenth-century hypothesis — a world orbiting inside Mercury, invented to explain a wobble in Mercury's orbit. Patterson's dictionary of the sea records it as settled fact in 1891. Einstein explained the wobble without it in 1915, and Vulcan quietly ceased to exist.