Richard Baum and William Sheehan. In Search of the Planet Vulcan: The Ghost in Newton's Clockwork Universe. Plenum trade, 1997.
This excellent piece of science history writing tells the story of the search for the phantom planet, Vulcan which was thought to lie inside the orbit of Mercury, and to explain anomalies in the orbit of that planet; similar anomalies in the orbit of Uranus having led to the discovery of Neptune. One of the foremost figures in that discovery, the leading French astronomer J. J. Le Verrier was the main protagonist in the search for the mystery planet or planets which were throught to be perturbing Mercury's orbit. Soon evidence for the mystery planet began to emerge, most importantly a sighting by the obscure country doctor, Lescarbault. Despite many searchers no real confirmation was ever found, though occasional sightings were recorded, most notably those by the American astronomers James C. Watson and his disciple Lewis Swift. The development of the general theory of relativity by Einstein explained the anomalies of Mercury's orbit without reference to Vulcan and the episode vanished into history.
This book is, of course, primarily aimed at a readership interested in a history of astronomy and covers a much wider ground than the search for Vulcan itself. It does mean that, though the authors make a passing reference to the similarity with the claimed discovery of the canals of Mars, they do. not really place the supposed discovery of Vulcan in the full context of pathological science.
Vulcan however fits in there perfectly; the charismatic promoter, the ambiguous observations made in difficult circumstances, the bandwagon jumpers, the failure of concerted searchers but just enough titbits of anecdotal evidence to whet the appetites of a small coterie of true believers. -- Peter Rogerson, from Magonia 61, November 1997.