The Longitude Problem The Royal Observatory of the British National Maritime Museum describes John Harrison's quest for The Longitude Prize. Contains great pictures of the Harrison chronometers.

The Mad Scientist Network Try it. You will enjoy it and can get answers to many questions

The Annals of Improbable Research Serious writers debunking some less serious folk.

Geoffrey Chaucer's "A Treatise on the Astrolabe" In old english, Mr Chaucer's note to his son. This is probably the first technical manual in English.

Chaucer; "Treatise on the Astrolabe" A translation into modern English of Chaucer's "Treatise on the Astrolabe" with links to other items of interest.

Navigation Methods navigation in John Cabot's time.