It was in the late autumn of 1867 that one of the most remarkable of the outrages committed by the Fenians in London took place. This was the explosion at the Clerkenwell House of Detention. The object of the crime was the rescue of two Fenians who were confined in the prison. The authorities at Scotland Yard had got wind of the plot, and sought to put the governor of the prison, and the magistrates who controlled it, on their guard. The latter declared themselves quite able to look after their prisoners, and declined the proffered assistance of the police. Instead of keeping guard, as they should have done, round the walls of the House of Detention, they contented themselves with keeping the prisoners--whose names, if my memory does not fail, were Burke and Casey--in their cells at the hour when they usually took their daily exercise in the yard. A wheelbarrow, laden with powerful explosives, was deliberately wheeled up to the prison wall, outside the exercise ground, at the time when Burke and Casey were supposed to be walking there. An orange was thrown over into the yard, this being the signal that had been agreed upon with the captives, and the fuse attached to the barrel of explosives was lighted. Then the conspirators quietly retired, nobody molesting them. A terrific explosion followed. I had just left the reading-room of the British Museum that afternoon, and was crossing the quadrangle, when I heard a sound which my experience of the Oaks Pit enabled me at once to recognise as that of an explosion. I thought that some kitchen boiler in an adjoining house must have burst; but nothing was to be seen, and I went my way, merely making a note, with the reporter's instinct, of the exact moment at which the explosion took place. The next morning the London papers were full of the details of the great crime. Several persons, including some children, had been killed outright, and many more had been injured. A breach had been made in the prison wall, but the Fenian prisoners, of course, had not escaped, owing to the precautions taken by the authorities. The whole country was roused to a violent state of indignation by this crime, which followed close upon a similar attempt to rescue other Fenian prisoners who were being carried in a prison van through the streets of Manchester. The Manchester crime resulted in the death of a police sergeant named Brett, and for that murder three men--Allen, Larkin, and Gould, who are still famous in Irish history as "the Manchester martyrs"--were hanged.