Autograph Letter Signed, to H.Gally Knight, thanking him for his letter and rejoicing at Gally Knight’s election to the Club. A good one page example. 7 x 4½ inches, minor creasing in one corner. Belle Vue House, Chelsea, 8 May 1830. Uncommon. Charles Hatchett (1765-1847) was the English chemist who discovered the element niobium. In 1801 while working for the British Museum in London, Hatchett analysed a piece of columbite in the museum’s collection. Columbite turned out to be a very complex mineral, and Hachett discovered that it contained a “new earth” which implied the existence of a new element. Hatchett called this new element columbium (Cb). On 26 November of that year he announced his discovery before the Royal Society. The element was later rediscovered and renamed niobium.