The last explosion of 1884 was on December 13th, and took the form of a considerable charge of dynamite or other nitro-compound under London Bridge. Very little damage was done, but there is no reasonable doubt that the perpetrators of this deed were themselves killed, and Colonel Majendie found what he believed to be the remains of a human being who was blown up with the boat employed in the transaction. Curiously enough, just previous to this outrage, circumstances led the authorities to believe that some of the bridges which span the Thames required special protection, and Her Majesty's Chief Inspector of Explosives was directed to visit them, and advise as to the precautions to be taken. Colonel Majendie found that London Bridge contained certain gully holes which were used for the purpose of draining out water. These gully holes possessed peculiar advantages for the secretion of an infernal machine. Accordingly, upon Colonel Majendie's recommendation, strong iron bars were placed over these holes, so that it was impossible to place the dynamite in the required position. The would-be perpetrators--and there were three of them--bungled so much that, as has already been hinted, little damage was done save to themselves. The facsimile of the bent bars and hooks (Fig. 22), much reduced, will give a good idea of the force of the explosive used on this occasion, and some idea of what the effects upon the bridge would have been if the bars had not been affixed and the charge had acted within the gully hole. [Illustration: FIG. 22.--RELICS OF LONDON BRIDGE EXPLOSION.] The last of the three bad years was 1885, in which year a brass tube or fuse for firing nitro-glycerine compound was found at Liverpool (Fig. 23): a very ingenious contrivance (here reproduced), in which sulphuric acid is used, the time at which the acid will act being governed by the number of folds of paper stuffed round the hole allowing the fluid to escape through, and so firing a detonator in conjunction with the explosive proper. Similar tubes had undoubtedly been used at Glasgow, at the Local Government Board Explosion, and at the _Times_ office. [Illustration: FIG. 23.--BRASS TUBE CONTAINING NITRO-GLYCERINE, FOUND AT LIVERPOOL.]