A MYSTERY is, in a popular sense, that which cannot be easily explained; a circumstance that cannot be readily accounted for. Something is, but how or why we cannot tell. The mysteries of modern London are as the sands of the seashore. The mighty city itself is a mystery. The lives of thousands of its inhabitants are mysteries. In the glare and clamour of the noonday, as in the darkness and silence of the night, the mysteries arise, sometimes to startle the world, sometimes to attract so litt...