Are both The Black Cauldron and In Search of the Castaways both based on books by Jules Verne?
no
In Search of the Castaways (film)
In Search of the Castaways is a 1962 Walt Disney Productions feature film starring Hayley Mills and Maurice Chevalier in a tale about a worldwide search for a shipwrecked sea captain.
 The film was directed by Robert Stevenson from a screenplay by Lowell S. Hawley based upon Jules Verne's 1868 adventure novel "Captain Grant's Children".
 The film was Mills' third of six for the Disney Studios.
The Black Cauldron (film)
The Black Cauldron is a 1985 American animated dark fantasy adventure film produced by Walt Disney Feature Animation in association with Silver Screen Partners II and released by Walt Disney Pictures.
 The 25th Disney animated feature film, it is loosely based on the first two books in "The Chronicles of Prydain" by Lloyd Alexander, a series of five novels that are, in turn, based on Welsh mythology.
A Drama in the Air
"A Drama in the Air" (French: ""'Un drame dans les airs'"" ) is an adventure short story by Jules Verne.
 The story was first published in August 1851 under the title "Science for families.
 A Voyage in a Balloon" ("La science en famille.
 Un voyage en ballon") in "Musée des familles" with five illustrations by Alexandre de Bar.
 In 1874, with six illustrations by Émile-Antoine Bayard, it was included in "Doctor Ox", the only collection of Jules Verne’s short stories published during Verne’s lifetime.
 An English translation by Anne T. Wilbur, published in May 1852 in "Sartain’s Union Magazine of Literature", marked the first time a work by Jules Verne was translated into the English language. Mysterious Island (1961 film)
Mysterious Island (UK: Jules Verne's Mysterious Island) is a 1961 science fiction adventure film about civil war prisoners who escape in a balloon and then find themselves stranded on a remote island populated by giant mutated animals.
 Based very loosely upon the 1874 novel "The Mysterious Island" ("L'Île mystérieuse") by Jules Verne (which was the sequel to two other novels by Verne, 1867's "In Search of the Castaways" and 1870's "Twenty Thousand Leagues Under the Sea"), the film was produced by Charles H. Schneer and directed by Cy Endfield.
 Shot in Spain and at Shepperton Studios, Shepperton, England, the film serves as a showcase for Ray Harryhausen's stop-motion animation effects.
 Like several of Harryhausen's classic productions, the musical score was composed by Bernard Herrmann. Michael Strogoff
Michael Strogoff: The Courier of the Czar (French: "Michel Strogoff" ) is a novel written by Jules Verne in 1876.
 Critics, including Leonard S. Davidow, consider it one of Verne's best books.
 Davidow wrote, "Jules Verne has written no better book than this, in fact it is deservedly ranked as one of the most thrilling tales ever written."
 Unlike some of Verne's other novels, it is not science fiction, but a scientific phenomenon (Leidenfrost effect) is a plot device.
 The book was later adapted to a play, by Verne himself and Adolphe d'Ennery.
 Incidental music to the play was written by Alexandre Artus in 1880.
 The book has been adapted several times for films, television and cartoon series. Jules Verne Award
Created in 1992 by Jean-Christophe Jeauffre and Frédéric Dieudonné, the two founders of the Jules Verne Festival, the Jules Verne Awards are a set of awards given annually for excellence exploration, environmental and cinematic achievements.
 Organized and overseen by The Jules Verne Adventures organization, the awards are given each year at a formal ceremony. Jules Verne ATV
The "Jules Verne" ATV, or Automated Transfer Vehicle 001 (ATV-001), was an unmanned cargo resupply spacecraft launched by the European Space Agency (ESA).
 The ATV was named after the 19th-century French science-fiction author Jules Verne.
 It was launched on 9 March 2008 on a mission to supply the International Space Station (ISS) with propellant, water, air, and dry cargo.
 "Jules Verne" was the first of five ATVs to be launched. The Castaways of the Flag
The Castaways of the Flag (French: "Seconde patrie" , lit.
 "Second Fatherland", 1900) is an adventure novel written by Jules Verne.
 The two volumes of the novel were initially published in English translation as two separate volumes: "Their Island Home" and "The Castaways of the Flag".
 Later reprints were published as "The Castaways of the Flag". The Children of Captain Grant (film)
The Children of Captain Grant Russian: Дети капитана Гранта , "Deti kapitana Granta " is a 1936 Soviet adventure film directed by Vladimir Vaynshtok and David Gutman and starring Nikolai Cherkasov, Ivan Chuvelyov and Yuri Yuryev.
 It is an adaptation of the novel "In Search of the Castaways" by Jules Verne.
 The film was popular on its release, and was followed in 1941 by another Verne adaptation "Mysterious Island".
 In the 1860s, two Scottish children go on a global search for their missing father, the sailor Captain Grant. The Mysterious Island
The Mysterious Island (French: "L'Île mystérieuse" ) is a novel by Jules Verne, published in 1874.
 The original edition, published by Hetzel, contains a number of illustrations by Jules Férat.
 The novel is a crossover sequel to Verne's famous "Twenty Thousand Leagues Under the Sea" and "In Search of the Castaways", though its themes are vastly different from those books.
 An early draft of the novel, initially rejected by Verne's publisher and wholly reconceived before publication, was titled "Shipwrecked Family: Marooned With Uncle Robinson," seen as indicating the influence on the novel of "Robinson Crusoe" and "The Swiss Family Robinson".
 Verne developed a similar theme in his later novel, "Godfrey Morgan" (French: "L'École des Robinsons", 1882).