For the tricentennial, it was revitalized with a fibre-glass dome; the old one made of papier-mâché and iron had been taken down. The telescope was installed by 1893, with 28-inch diameter glass doublet lens made by Grubb from Chance of Birmingham glass. The new dome was made by T. Cooke and Sons. This replaced a smaller drum-shaped dome. The Lassel two-foot reflector was a famous metal-mirror telescope that had been used to discover the Moons Triton and Hyperion. It was donated to the observatory in the 1880s, but was taken down in the 1890s. The 1890s also saw the construction of the "Altazimuth Pavilion", completed in 1896 and designed by William Crisp. In 1898 the Christie Enclosure was established to house sensitive magnetic instruments that had been disrupted by the use of iron at the main facility. The Observatory underwent an attempted bombing on 15 February 1894. This was possibly the first "international terrorist" incident in Britain. The bomb was accidentally detonated while being held by 26-year-old French anarchist Martial Bourdin in Greenwich Park, near the Observatory building. Bourdin died about 30 minutes later. It is not known why he chose the observatory, or whether the detonation was intended to occur elsewhere. The novelist Joseph Conrad used the incident in his novel "The Secret Agent". For major parts of the twentieth century, the Royal Greenwich Observatory was not at Greenwich, because it moved to Herstmonceux in Sussex in 1957. The last time that all departments were in Greenwich was 1924: in that year electrification of the railways affected the readings of the Magnetic and Meteorological Departments, and the Magnetic Observatory moved to Abinger in Surrey. Prior to this, the observatory had had to insist that the electric trams in the vicinity could not use an earth return for the traction current. After the onset of World War II in 1939, many departments were temporarily evacuated out of range of German bombers, to Abinger, Bradford on Avon, Bristol, and Bath, and activities in Greenwich were reduced to the bare minimum. On 15 October 1940, during the Blitz, the Courtyard gates were destroyed by a direct bomb hit. The wall above the Gate Clock collapsed, and the clock's dial was damaged. The damage was repaired after the war. After the Second World War, in 1947, the decision was made to move the Royal Observatory to Herstmonceux Castle and 320 adjacent acres (1.3 km²), 70 km south-southeast of Greenwich near Hailsham in East Sussex, due to light pollution in London.