His largest telescope was the 25-inch (0.64-m) Newall refractor, at the time the largest in the world, made in 1868 for Robert Stirling Newall (1812–89), a wealthy English amateur astronomer. In 1890 Newall gave it to Cambridge University, who in 1957 donated it to the National Observatory of Athens, Greece. In 1922 the Cooke firm merged with an instrument company set up by Edward Troughton (1753–1835) and William Simms (1793–1860).