If life is not always poetical, it is at least metrical. Periodicity rules over the mental experience of man, according to the path of the orbit of his thoughts. Distances are not gauged, ellipses not measured, velocities not ascertained, times not known. Nevertheless, the recurrence is sure. What the mind suffered last week, or last year, it does not suffer now; but it will suffer again next week or next year. Happiness is not a matter of events; it depends upon the tides of the mind. Disease is metrical, closing in at shorter and shorter periods towards death, sweeping abroad at longer and longer intervals towards recovery. Sorrow for one cause was intolerable yesterday, and will be intolerable tomorrow; today it is easy to bear, but the cause has not passed. Even the burden of a spiritual distress unsolved is bound to leave the heart to a temporary peace; and remorse itself does not remain -- it returns. Gaiety takes us by a dear surprise. If we had made a course of notes of its visits, we might have been on the watch, and would have had an expectation instead of a discovery. No one makes such observations; in all the diaries of students of the interior world, there have never come to light the records of the Kepler of such cycles. But Thomas e Kempis knew of the recurrences, if he did not measure them. In his cell alone with the elements -- ‘What wouldst thou more than these? for out of these were all things made’ -- he learnt the stay to be found in the depth of the hour of bitterness, and the remembrance that restrains the soul at the coming of the moment of delight, giving it a more conscious welcome, but presaging for it an inexorable flight. And ‘rarely, rarely comest thou,’ sighed Shelley, not to Delight merely, but to the Spirit of Delight. Delight can be compelled beforehand, called, and constrained to our service—Ariel can be bound to a daily task; but such artificial violence throws life out of metre, and i...