For years, the works made barely enough money to cover the workmen's wages. Then, in 1841, Alfred's brother Hermann invented the spoon-roller—which Alfred patented, bringing in enough money to enlarge the factory, steel production, and cast steel blocks. In 1847 Krupp made his first cannon of cast steel. At the Great Exhibition (London) of 1851, he exhibited a 6 pounder made entirely from cast steel, and a solid flawless ingot of steel weighing , more than twice as much as any previously cast. He surpassed this with a ingot for the Paris Exposition in 1855. Krupp's exhibits caused a sensation in the engineering world, and the Essen works became famous.