The greatest discovery ever achieved by man is beyond all question that which it is now our privilege to announce, namely, that of the new Prospective Telegraph . By this truly wonderful invention (exquisitely simple in its machinery, yet of surpassing power) the obstacle of Time is as effectually conquered as that of Space has been for the last generation by the Electric Telegraph; and future years—even, it is anticipated, future centuries—will be made to respond to our call as promptly and com