Autograph Letter Signed, to ‘Dear Rackett’, rejoicing at his arrival in Gower Street, and inviting him and Mr. and Mrs. Solly to dinner. A good one page example. 7 x 4½ inches. Belle Vue House, Chelsea, 13 November 1835. 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 Hatchett 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.